Access point (ap), station (sta) and method of multi-user (mu) location measurment

ABSTRACT

Embodiments of an access point (AP), station (STA) and method for multi-user (MU) location measurement are generally described herein. The AP may contend for a transmission opportunity (TXOP) to obtain access to a channel. The AP may transmit a trigger frame (TF) to initiate a multi-user (MU) location measurement during the TXOP. The AP may receive service requests for the MU location measurement from a plurality of STAs. The AP may transmit an MU acknowledgement (ACK) frame that indicates reception of the service requests. The AP may receive, from the STAs, uplink sounding frames that include per-STA timing information for the service requests and the MU ACK frame. The STA may determine location measurements for the STAs based on the per-STA timing information included in the uplink sounding frames.

PRIORITY CLAIM

This application claims priority under 35 USC 119(e) to U.S. ProvisionalPatent Application Ser. No. 62/315,242, filed Mar. 30, 2016 [referencenumber P97440Z (9884.003PRV)] and U.S. Provisional Patent ApplicationSer. No. 62/315,248, filed Mar. 30, 2016 [reference number P97441Z(9884.004PRV)], both of which are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

Embodiments pertain to wireless networks. Some embodiments relate towireless local area networks (WLANs) and Wi-Fi networks includingnetworks operating in accordance with the IEEE 802.11 family ofstandards, such as the IEEE 802.11ac standard or the IEEE 802.11ax studygroup (SG). Some embodiments relate to high-efficiency (HE) wireless orhigh-efficiency WLAN or Wi-Fi communications. Some embodiments relate tochannel access. Some embodiments relate to spatial reuse. Someembodiments relate to channel access in accordance with omni-directionaland/or directional patterns.

BACKGROUND

Wireless communications have been evolving toward ever increasing datarates (e.g., from IEEE 802.11a/g to IEEE 802.11n to IEEE 802.11ac andIEEE 802.11ad). In high-density deployment situations, overall systemefficiency may become more important than higher data rates. Forexample, in high-density hotspot and cellular offloading scenarios, manydevices competing for the wireless medium may have low to moderate datarate requirements (with respect to the very high data rates of IEEE802.11ac). A recently-formed study group for Wi-Fi evolution referred toas the IEEE 802.11 High Efficiency WLAN (HEW) study group (SG) (i.e.,IEEE 802.11ax) is addressing these high-density deployment scenarios. Inaddition, IEEE 802.11ad, IEEE 802.11ay and/or other technologies may beused in these and other scenarios, in some cases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless network in accordance with someembodiments;

FIG. 2 illustrates an example machine in accordance with someembodiments;

FIG. 3 illustrates a station (STA) in accordance with some embodimentsand an access point (AP) in accordance with some embodiments;

FIG. 4 is a block diagram of a radio architecture in accordance withsome embodiments;

FIG. 5 illustrates a front-end module circuitry for use in the radioarchitecture of FIG. 4 in accordance with some embodiments;

FIG. 6 illustrates a radio IC circuitry for use in the radioarchitecture of FIG. 4 in accordance with some embodiments;

FIG. 7 illustrates a baseband processing circuitry for use in the radioarchitecture of FIG. 4 in accordance with some embodiments;

FIG. 8 illustrates the operation of a method of communication inaccordance with some embodiments;

FIG. 9 illustrates example operations in accordance with someembodiments;

FIG. 10 illustrates example frames in accordance with some embodiments;

FIG. 11 illustrates the operation of another method of communication inaccordance with some embodiments;

FIG. 12 illustrates the operation of another method of communication inaccordance with some embodiments;

FIG. 13 illustrates additional example operations in accordance withsome embodiments;

FIG. 14 illustrates additional example frames in accordance with someembodiments; and

FIG. 15 illustrates the operation of another method of communication inaccordance with some embodiments.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

FIG. 1 illustrates a wireless network in accordance with someembodiments. In some embodiments, the network 100 may be a HighEfficiency (HE) Wireless Local Area Network (WLAN) network. In someembodiments, the network 100 may be a WLAN or a Wi-Fi network. Theseembodiments are not limiting, however, as some embodiments of thenetwork 100 may include a combination of such networks. That is, thenetwork 100 may support MU operation (for example HE) devices in somecases, non MU operation devices in some cases, and a combination of MUoperation devices and non MU operation devices in some cases.Accordingly, it is understood that although techniques described hereinmay refer to either a non MU operation device or to an MU operationdevice, such techniques may be applicable to both non MU operationdevices and MU operation devices in some cases.

Referring to FIG. 1, the network 100 may include any or all of thecomponents shown, and embodiments are not limited to the number of eachcomponent shown in FIG. 1. In some embodiments, the network 100 mayinclude a master station (AP) 102 and may include any number (includingzero) of stations (STAs) 103 and/or HE devices 104. In some embodiments,the AP 102 may receive and/or detect signals from one or more STAs 103,and may transmit data packets to one or more STAs 103. These embodimentswill be described in more detail below.

The AP 102 may be arranged to communicate with one or more of thecomponents shown in FIG. 1 in accordance with one or more IEEE 802.11standards (including 802.11ax and/or others), other standards and/orother communication protocols. It should be noted that embodiments arenot limited to usage of an AP 102. References herein to the AP 102 arenot limiting and references herein to the master station 102 are alsonot limiting. In some embodiments, a STA 103, an MU operation device(device capable of MU operation), an HE device 104 and/or other devicemay be configurable to operate as a master station. Accordingly, in suchembodiments, operations that may be performed by the AP 102 as describedherein may be performed by the STA 103, an MU operation device, an HEdevice 104 and/or other device that is configurable to operate as themaster station.

In some embodiments, one or more of the STAs 103 may be legacy stations(for instance, a non MU operation device and/or device not capable of MUoperation). These embodiments are not limiting, however, as the STAs 103may be configured to operate as MU operation devices. HE devices 104 ormay support MU operation or may support HE operation, in someembodiments. The master station 102 may be arranged to communicate withthe STAs 103 and/or the HE stations and/or the MU operation stations inaccordance with one or more of the IEEE 802.11 standards, including802.11ax and/or others. In accordance with some HE operation embodimentsand/or MU operation embodiments, an access point (AP) may operate as themaster station 102 and may be arranged to contend for a wireless medium(e.g., during a contention period) to receive exclusive control of themedium for an 802.11 air access control period (i.e., a transmissionopportunity (TXOP)). The master station 102 may, for example, transmit amaster-sync or control transmission at the beginning of the 802.11 airaccess control period (including but not limited to an HE controlperiod) to indicate, among other things, which MU operation stationsand/or HE stations 104 are scheduled for communication during the 802.11air access control period. During the 802.11 air access control period,the scheduled MU operation stations 104 may communicate with the masterstation 102 in accordance with a non-contention based multiple accesstechnique. This is unlike conventional Wi-Fi communications in whichdevices communicate in accordance with a contention-based communicationtechnique, rather than a non-contention based multiple access technique.During the 802.11 air access control period, the master station 102 maycommunicate with HE stations 104 using one or more MU PPDUs. During the802.11 air access control period, STAs 103 not operating as MU operationdevices may refrain from communicating in some cases. In someembodiments, the master-sync transmission may be referred to as acontrol and schedule transmission.

In some embodiments, the multiple-access technique used during the802.11 air access control period may be a scheduled orthogonalfrequency-division multiple access (OFDMA) technique, although this isnot a requirement. In some embodiments, the multiple access techniquemay be a time-division multiple access (TDMA) technique or afrequency-division multiple access (FDMA) technique. In someembodiments, the multiple access technique may be a space-divisionmultiple access (SDMA) technique including a multi-user (MU)multiple-input multiple-output (MIMO) (MU-MIMO) technique or combinationof the above. These multiple-access techniques used during the 802.11air access control period may be configured for uplink or downlink datacommunications.

The master station 102 may also communicate with STAs 103 and/or otherlegacy stations in accordance with legacy IEEE 802.11 communicationtechniques. In some embodiments, the master station 102 may also beconfigurable to communicate with the MU operation stations and/or HEstations 104 outside the 802.11 air access control period in accordancewith legacy IEEE 802.11 communication techniques, although this is not arequirement.

In some embodiments, the MU communications during the control period maybe configurable to use one of 20 MHz, 40 MHz, or 80 MHz contiguousbandwidths or an 80+80 MHz (160 MHz) non-contiguous bandwidth. In someembodiments, a 320 MHz channel width may be used. In some embodiments,sub-channel bandwidths less than 20 MHz may also be used. In theseembodiments, each channel or sub-channel of an MU communication may beconfigured for transmitting a number of spatial streams.

In some embodiments, MU techniques may be used, although the scope ofembodiments is not limited in this respect. As an example, techniquesincluded in 802.11ax standards and/or other standards may be used. Inaccordance with some embodiments, a master station 102 and/or MUoperation stations and/or HE stations 104 may generate an MU packet inaccordance with a short preamble format or a long preamble format. TheMU packet may comprise a legacy signal field (L-SIG) followed by one ormore MU signal fields (HE-SIG) and an MU long-training field (MU-LTF).For the short preamble format, the fields may be configured forshorter-delay spread channels. For the long preamble format, the fieldsmay be configured for longer-delay spread channels. These embodimentsare described in more detail below. It should be noted that the terms“HEW” and “HE” may be used interchangeably and both terms may refer tohigh-efficiency Wireless Local Area Network operation and/orhigh-efficiency Wi-Fi operation.

As used herein, the term “circuitry” may refer to, be part of, orinclude an Application Specific Integrated Circuit (ASIC), an electroniccircuit, a processor (shared, dedicated, or group), and/or memory(shared, dedicated, or group) that execute one or more software orfirmware programs, a combinational logic circuit, and/or other suitablehardware components that provide the described functionality. In someembodiments, the circuitry may be implemented in, or functionsassociated with the circuitry may be implemented by, one or moresoftware or firmware modules. In some embodiments, circuitry may includelogic, at least partially operable in hardware. Embodiments describedherein may be implemented into a system using any suitably configuredhardware and/or software.

FIG. 2 illustrates a block diagram of an example machine in accordancewith some embodiments. The machine 200 is an example machine upon whichany one or more of the techniques and/or methodologies discussed hereinmay be performed. In alternative embodiments, the machine 200 mayoperate as a standalone device or may be connected (e.g., networked) toother machines. In a networked deployment, the machine 200 may operatein the capacity of a server machine, a client machine, or both inserver-client network environments. In an example, the machine 200 mayact as a peer machine in peer-to-peer (P2P) (or other distributed)network environment. The machine 200 may be an AP 102, STA 103, HEdevice, HE AP, HE STA, UE, eNB, mobile device, base station, personalcomputer (PC), a tablet PC, a set-top box (STB), a personal digitalassistant (PDA), a mobile telephone, a smart phone, a web appliance, anetwork router, switch or bridge, or any machine capable of executinginstructions (sequential or otherwise) that specify actions to be takenby that machine. Further, while only a single machine is illustrated,the term “machine” shall also be taken to include any collection ofmachines that individually or jointly execute a set (or multiple sets)of instructions to perform any one or more of the methodologiesdiscussed herein, such as cloud computing, software as a service (SaaS),other computer cluster configurations.

Examples as described herein, may include, or may operate on, logic or anumber of components, modules, or mechanisms. Modules are tangibleentities (e.g., hardware) capable of performing specified operations andmay be configured or arranged in a certain manner. In an example,circuits may be arranged (e.g., internally or with respect to externalentities such as other circuits) in a specified manner as a module. Inan example, the whole or part of one or more computer systems (e g., astandalone, client or server computer system) or one or more hardwareprocessors may be configured by firmware or software (e.g.,instructions, an application portion, or an application) as a modulethat operates to perform specified operations. In an example, thesoftware may reside on a machine readable medium. In an example, thesoftware, when executed by the underlying hardware of the module, causesthe hardware to perform the specified operations.

Accordingly, the term “module” is understood to encompass a tangibleentity, be that an entity that is physically constructed, specificallyconfigured (e.g., hardwired), or temporarily (e.g., transitorily)configured (e.g., programmed) to operate in a specified manner or toperform part or all of any operation described herein. Consideringexamples in which modules are temporarily configured, each of themodules need not be instantiated at any one moment in time. For example,where the modules comprise a general-purpose hardware processorconfigured using software, the general-purpose hardware processor may beconfigured as respective different modules at different times. Softwaremay accordingly configure a hardware processor, for example, toconstitute a particular module at one instance of time and to constitutea different module at a different instance of time.

The machine (e.g., computer system) 200 may include a hardware processor202 (e.g., a central processing unit (CPU), a graphics processing unit(GPU), a hardware processor core, or any combination thereof), a mainmemory 204 and a static memory 206, some or all of which may communicatewith each other via an interlink (e.g., bus) 208. The machine 200 mayfurther include a display unit 210, an alphanumeric input device 212(e.g., a keyboard), and a user interface (UI) navigation device 214 (eg., a mouse). In an example, the display unit 210, input device 212 andUI navigation device 214 may be a touch screen display. The machine 200may additionally include a storage device (e.g., drive unit) 216, asignal generation device 218 (e g., a speaker), a network interfacedevice 220, and one or more sensors 221, such as a global positioningsystem (GPS) sensor, compass, accelerometer, or other sensor. Themachine 200 may include an output controller 228, such as a serial(e.g., universal serial bus (USB)), parallel, or other wired or wireless(e.g., infrared (IR), near field communication (NFC), etc.) connectionto communicate or control one or more peripheral devices (e g., aprinter, card reader, etc.).

The storage device 216 may include a machine readable medium 222 onwhich is stored one or more sets of data structures or instructions 224(e.g., software) embodying or utilized by any one or more of thetechniques or functions described herein. The instructions 224 may alsoreside, completely or at least partially, within the main memory 204,within static memory 206, or within the hardware processor 202 duringexecution thereof by the machine 200. In an example, one or anycombination of the hardware processor 202, the main memory 204, thestatic memory 206, or the storage device 216 may constitute machinereadable media. In some embodiments, the machine readable medium may beor may include a non-transitory computer-readable storage medium. Insome embodiments, the machine readable medium may be or may include acomputer-readable storage medium.

While the machine readable medium 222 is illustrated as a single medium,the term “machine readable medium” may include a single medium ormultiple media (e g., a centralized or distributed database, and/orassociated caches and servers) configured to store the one or moreinstructions 224. The term “machine readable medium” may include anymedium that is capable of storing, encoding, or carrying instructionsfor execution by the machine 200 and that cause the machine 200 toperform any one or more of the techniques of the present disclosure, orthat is capable of storing, encoding or carrying data structures used byor associated with such instructions. Non-limiting machine readablemedium examples may include solid-state memories, and optical andmagnetic media. Specific examples of machine readable media may include:non-volatile memory, such as semiconductor memory devices (e.g.,Electrically Programmable Read-Only Memory (EPROM), ElectricallyErasable Programmable Read-Only Memory (EEPROM)) and flash memorydevices, magnetic disks, such as internal hard disks and removabledisks, magneto-optical disks; Random Access Memory (RAM); and CD-ROM andDVD-ROM disks. In some examples, machine readable media may includenon-transitory machine readable media. In some examples, machinereadable media may include machine readable media that is not atransitory propagating signal.

The instructions 224 may further be transmitted or received over acommunications network 226 using a transmission medium via the networkinterface device 220 utilizing any one of a number of transfer protocols(e.g., frame relay, internet protocol (IP), transmission controlprotocol (TCP), user datagram protocol (UDP), hypertext transferprotocol (HTTP), etc.). Example communication networks may include alocal area network (LAN), a wide area network (WAN), a packet datanetwork (e.g., the Internet), mobile telephone networks (e.g., cellularnetworks). Plain Old Telephone Service (POTS) networks, and wirelessdata networks (e.g., Institute of Electrical and Electronics Engineers(IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16 family ofstandards known as WiMax®), IEEE 802.15.4 family of standards, a LongTerm Evolution (LTE) family of standards, a Universal MobileTelecommunications System (UMTS) family of standards, peer-to-peer (P2P)networks, among others. In an example, the network interface device 220may include one or more physical jacks (e g., Ethernet, coaxial, orphone jacks) or one or more antennas to connect to the communicationsnetwork 226. In an example, the network interface device 220 may includea plurality of antennas to wirelessly communicate using at least one ofsingle-input multiple-output (SIMO), multiple-input multiple-output(MIMO), or multiple-input single-output (MISO) techniques. In someexamples, the network interface device 220 may wirelessly communicateusing Multiple User MIMO techniques, OFDMA techniques and combination.The term “transmission medium” shall be taken to include any intangiblemedium that is capable of storing, encoding or carrying instructions forexecution by the machine 200, and includes digital or analogcommunications signals or other intangible medium to facilitatecommunication of such software.

FIG. 3 illustrates a station (STA) in accordance with some embodimentsand an access point (AP) in accordance with some embodiments. It shouldbe noted that in some embodiments, an STA or other mobile device mayinclude some or all of the components shown in either FIG. 2 or FIG. 3(as in 300) or both. The STA 300 may be suitable for use as an STA 103as depicted in FIG. 1, in some embodiments. It should also be noted thatin some embodiments, an AP or other base station may include some or allof the components shown in either FIG. 2 or FIG. 3 (as in 350) or both.The AP 350 may be suitable for use as an AP 102 as depicted in FIG. 1,in some embodiments.

The STA 300 may include physical layer circuitry 302 and a transceiver305, one or both of which may enable transmission and reception ofsignals to and from components such as the AP 102 (FIG. 1), other STAsor other devices using one or more antennas 301. As an example, thephysical layer circuitry 302 may perform various encoding and decodingfunctions that may include formation of baseband signals fortransmission and decoding of received signals. As another example, thetransceiver 305 may perform various transmission and reception functionssuch as conversion of signals between a baseband range and a RadioFrequency (RF) range. Accordingly, the physical layer circuitry 302 andthe transceiver 305 may be separate components or may be part of acombined component. In addition, some of the described functionalityrelated to transmission and reception of signals may be performed by acombination that may include one, any or all of the physical layercircuitry 302, the transceiver 305, and other components or layers. TheSTA 300 may also include medium access control (MAC) layer circuitry 304for controlling access to the wireless medium. The STA 300 may alsoinclude processing circuitry 306 and memory 308 arranged to perform theoperations described herein.

The AP 350 may include physical layer circuitry 352 and a transceiver355, one or both of which may enable transmission and reception ofsignals to and from components such as the STA 103 (FIG. 1), other APsor other devices using one or more antennas 351. As an example, thephysical layer circuitry 352 may perform various encoding and decodingfunctions that may include formation of baseband signals fortransmission and decoding of received signals. As another example, thetransceiver 355 may perform various transmission and reception functionssuch as conversion of signals between a baseband range and a RadioFrequency (RF) range. Accordingly, the physical layer circuitry 352 andthe transceiver 355 may be separate components or may be part of acombined component. In addition, some of the described functionalityrelated to transmission and reception of signals may be performed by acombination that may include one, any or all of the physical layercircuitry 352, the transceiver 355, and other components or layers. TheAP 350 may also include medium access control (MAC) layer circuitry 354for controlling access to the wireless medium. The AP 350 may alsoinclude processing circuitry 356 and memory 358 arranged to perform theoperations described herein.

The antennas 301, 351, 230 may comprise one or more directional oromnidirectional antennas, including, for example, dipole antennas,monopole antennas, patch antennas, loop antennas, microstrip antennas orother types of antennas suitable for transmission of RF signals. In somemultiple-input multiple-output (MIMO) embodiments, the antennas 301,351, 230 may be effectively separated to take advantage of spatialdiversity and the different channel characteristics that may result.

In some embodiments, the STA 300 may be configured as an HE device 104(FIG. 1), and may communicate using OFDM and/or OFDMA communicationsignals over a multicarrier communication channel. In some embodiments,the AP 350 may be configured to communicate using OFDM and/or OFDMAcommunication signals over a multicarrier communication channel. In someembodiments, the HE device 104 may be configured to communicate usingOFDM communication signals over a multicarrier communication channel.Accordingly, in some cases, the STA 300, AP 350 and/or HE device 104 maybe configured to receive signals in accordance with specificcommunication standards, such as the Institute of Electrical andElectronics Engineers (IEEE) standards including IEEE 802.11-2012,802.11n-2009 and/or 802.11ac-2013 and/or 802.11ad and/or 802.11ahstandards and/or proposed specifications for WLANs including proposed HEstandards, although the scope of the embodiments is not limited in thisrespect as they may also be suitable to transmit and/or receivecommunications in accordance with other techniques and standards. Insome other embodiments, the AP 350, HE device 104 and/or the STA 300configured as an HE device 104 may be configured to receive signals thatwere transmitted using one or more other modulation techniques such asspread spectrum modulation (e.g., direct sequence code division multipleaccess (DS-CDMA) and/or frequency hopping code division multiple access(FH-CDMA)), time-division multiplexing (TDM) modulation, and/orfrequency-division multiplexing (FDM) modulation, although the scope ofthe embodiments is not limited in this respect. Embodiments disclosedherein provide two preamble formats for High Efficiency (HE) WirelessLAN standards specification that is under development in the IEEE TaskGroup 11ax (TGax).

In some embodiments, the STA 300 and/or AP 350 may be a mobile deviceand may be a portable wireless communication device, such as a personaldigital assistant (PDA), a laptop or portable computer with wirelesscommunication capability, a web tablet, a wireless telephone, asmartphone, a wireless headset, a pager, an instant messaging device, adigital camera, an access point, a television, a wearable device such asa medical device (e.g., a heart rate monitor, a blood pressure monitor,etc), or other device that may receive and/or transmit informationwirelessly. In some embodiments, the STA 300 and/or AP 350 may beconfigured to operate in accordance with 802.11 standards, although thescope of the embodiments is not limited in this respect. Mobile devicesor other devices in some embodiments may be configured to operateaccording to other protocols or standards, including other IEEEstandards, Third Generation Partnership Project (3GPP) standards orother standards. In some embodiments, the STA 300 and/or AP 350 mayinclude one or more of a keyboard, a display, a non-volatile memoryport, multiple antennas, a graphics processor, an application processor,speakers, and other mobile device elements. The display may be an LCDscreen including a touch screen.

Although the STA 300 and the AP 350 are each illustrated as havingseveral separate functional elements, one or more of the functionalelements may be combined and may be implemented by combinations ofsoftware-configured elements, such as processing elements includingdigital signal processors (DSPs), and/or other hardware elements. Forexample, some elements may comprise one or more microprocessors, DSPs,field-programmable gate arrays (FPGAs), application specific integratedcircuits (ASICs), radio-frequency integrated circuits (RFICs) andcombinations of various hardware and logic circuitry for performing atleast the functions described herein. In some embodiments, thefunctional elements may refer to one or more processes operating on oneor more processing elements.

Embodiments may be implemented in one or a combination of hardware,firmware and software. Embodiments may also be implemented asinstructions stored on a computer-readable storage device, which may beread and executed by at least one processor to perform the operationsdescribed herein. A computer-readable storage device may include anynon-transitory mechanism for storing information in a form readable by amachine (e.g., a computer). For example, a computer-readable storagedevice may include read-only memory (ROM), random-access memory (RAM),magnetic disk storage media, optical storage media, flash-memorydevices, and other storage devices and media. Some embodiments mayinclude one or more processors and may be configured with instructionsstored on a computer-readable storage device.

It should be noted that in some embodiments, an apparatus used by theSTA 300 may include various components of the STA 300 as shown in FIG. 3and/or the example machine 200 as shown in FIG. 2. Accordingly,techniques and operations described herein that refer to the STA 300 (or103) may be applicable to an apparatus for an STA, in some embodiments.It should also be noted that in some embodiments, an apparatus used bythe AP 350 may include various components of the AP 350 as shown in FIG.3 and/or the example machine 200 as shown in FIG. 2. Accordingly,techniques and operations described herein that refer to the AP 350 (or102) may be applicable to an apparatus for an AP, in some embodiments.In addition, an apparatus for a mobile device and/or base station mayinclude one or more components shown in FIGS. 2-3, in some embodiments.Accordingly, techniques and operations described herein that refer to amobile device and/or base station may be applicable to an apparatus fora mobile device and/or base station, in some embodiments.

FIG. 4 is a block diagram of a radio architecture 400 in accordance withsome embodiments. Radio architecture 400 may include radio front-endmodule (FEM) circuitry 404, radio IC circuitry 406 and basebandprocessing circuitry 408. Radio architecture 400 as shown includes bothWireless Local Area Network (WLAN) functionality and Bluetooth (BT)functionality although embodiments are not so limited. In thisdisclosure, “WLAN” and “Wi-Fi” are used interchangeably.

FEM circuitry 404 may include a WLAN or Wi-Fi FEM circuitry 404A and aBluetooth (BT) FEM circuitry 404B. The WLAN FEM circuitry 404 a mayinclude a receive signal path comprising circuitry configured to operateon WLAN RF signals received from one or more antennas 401, to amplifythe received signals and to provide the amplified versions of thereceived signals to the WLAN radio IC circuitry 406A for furtherprocessing. The BT FEM circuitry 404B may include a receive signal pathwhich may include circuitry configured to operate on BT RF signalsreceived from one or more antennas 401, to amplify the received signalsand to provide the amplified versions of the received signals to the BTradio IC circuitry 406B for further processing. FEM circuitry 404A mayalso include a transmit signal path which may include circuitryconfigured to amplify WLAN signals provided by the radio IC circuitry406A for wireless transmission by one or more of the antennas 401. Inaddition, FEM circuitry 404B may also include a transmit signal pathwhich may include circuitry configured to amplify BT signals provided bythe radio IC circuitry 406B for wireless transmission by the one or moreantennas. In the embodiment of FIG. 4, although FEM 404A and FEM 404Bare shown as being distinct from one another, embodiments are not solimited, and include within their scope the use of an FEM (not shown)that includes a transmit path and/or a receive path for both WLAN and BTsignals, or the use of one or more FEM circuitries where at least someof the FEM circuitries share transmit and/or receive signal paths forboth WLAN and BT signals.

Radio IC circuitry 406 as shown may include WLAN radio IC circuitry 406Aand BT radio IC circuitry 406B. The WLAN radio IC circuitry 406 a mayinclude a receive signal path which may include circuitry todown-convert WLAN RF signals received from the FEM circuitry 404A andprovide baseband signals to WLAN baseband processing circuitry 408A. BTradio IC circuitry 406B may in turn include a receive signal path whichmay include circuitry to down-convert BT RF signals received from theFEM circuitry 404B and provide baseband signals to BT basebandprocessing circuitry 408B. WLAN radio IC circuitry 406A may also includea transmit signal path which may include circuitry to up-convert WLANbaseband signals provided by the WLAN baseband processing circuitry 408a and provide WLAN RF output signals to the FEM circuitry 404A forsubsequent wireless transmission by the one or more antennas 401. BTradio IC circuitry 406B may also include a transmit signal path whichmay include circuitry to up-convert BT baseband signals provided by theBT baseband processing circuitry 408B and provide BT RF output signalsto the FEM circuitry 404B for subsequent wireless transmission by theone or more antennas 401. In the embodiment of FIG. 4, although radio ICcircuitries 406A and 406B are shown as being distinct from one another,embodiments are not so limited, and include within their scope the useof a radio IC circuitry (not shown) that includes a transmit signal pathand/or a receive signal path for both WLAN and BT signals, or the use ofone or more radio IC circuitries where at least some of the radio ICcircuitries share transmit and/or receive signal paths for both WLAN andBT signals.

Baseband processing circuitry 408 may include a WLAN baseband processingcircuitry 408A and a BT baseband processing circuitry 408B. The WLANbaseband processing circuitry 408A may include a memory, such as, forexample, a set of RAM arrays in a Fast Fourier Transform or Inverse FastFourier Transform block (not shown) of the WLAN baseband processingcircuitry 408A. Each of the WLAN baseband circuitry 408A and the BTbaseband circuitry 408B may further include one or more processors andcontrol logic to process the signals received from the correspondingWLAN or BT receive signal path of the radio IC circuitry 406, and toalso generate corresponding WLAN or BT baseband signals for the transmitsignal path of the radio IC circuitry 406. Each of the basebandprocessing circuitries 408A and 408B may further include physical layer(PHY) and medium access control layer (MAC) circuitry, and may furtherinterface with application processor 411 for generation and processingof the baseband signals and for controlling operations of the radio ICcircuitry 406.

Referring still to FIG. 4, according to the shown embodiment, WLAN-BTcoexistence circuitry 413 may include logic providing an interfacebetween the WLAN baseband circuitry 408A and the BT baseband circuitry408B to enable use cases requiring WLAN and BT coexistence. In addition,a switch 403 may be provided between the WLAN FEM circuitry 404 a andthe BT FEM circuitry 404B to allow switching between the WLAN and BTradios according to application needs. In addition, although theantennas 401 are depicted as being respectively connected to the WLANFEM circuitry 404A and the BT FEM circuitry 404B, embodiments includewithin their scope the sharing of one or more antennas as between theWLAN and BT FEMs, or the provision of more than one antenna connected toeach of FEM 404A or 404B.

In some embodiments, the front-end module circuitry 404, the radio ICcircuitry 406, and baseband processing circuitry 408 may be provided ona single radio card, such as wireless radio card 402. In some otherembodiments, the one or more antennas 401, the FEM circuitry 404 and theradio IC circuitry 406 may be provided on a single radio card. In someother embodiments, the radio IC circuitry 406 and the basebandprocessing circuitry 408 may be provided on a single chip or integratedcircuit (IC), such as IC 412.

In some embodiments, the wireless radio card 402 may include a WLANradio card and may be configured for Wi-Fi communications, although thescope of the embodiments is not limited in this respect. In some ofthese embodiments, the radio architecture 400 may be configured toreceive and transmit orthogonal frequency division multiplexed (OFDM) ororthogonal frequency division multiple access (OFDMA) communicationsignals over a multicarrier communication channel. The OFDM or OFDMAsignals may comprise a plurality of orthogonal subcarriers.

In some of these multicarrier embodiments, radio architecture 400 may bepart of a Wi-Fi communication station (STA) such as a wireless accesspoint (AP), a base station or a mobile device including a Wi-Fi device.In some of these embodiments, radio architecture 400 may be configuredto transmit and receive signals in accordance with specificcommunication standards and/or protocols, such as any of the Instituteof Electrical and Electronics Engineers (IEEE) standards including,802.11n-2009, IEEE 802.11-2016, 802.11n-2009, 802.11ac, and/or 802.11axstandards and/or proposed specifications for WLANs, although the scopeof embodiments is not limited in this respect. Radio architecture 400may also be suitable to transmit and/or receive communications inaccordance with other techniques and standards.

In some embodiments, the radio architecture 400 may be configured forhigh-efficiency (HE) Wi-Fi (HEW) communications in accordance with theIEEE 802.11ax standard. In these embodiments, the radio architecture 400may be configured to communicate in accordance with an OFDMA technique,although the scope of the embodiments is not limited in this respect.

In some other embodiments, the radio architecture 400 may be configuredto transmit and receive signals transmitted using one or more othermodulation techniques such as spread spectrum modulation (e.g., directsequence code division multiple access (DS-CDMA) and/or frequencyhopping code division multiple access (FH-CDMA)), time-divisionmultiplexing (TDM) modulation, and/or frequency-division multiplexing(FDM) modulation, although the scope of the embodiments is not limitedin this respect.

In some embodiments, as further shown in FIG. 4, the BT basebandcircuitry 408B may be compliant with a Bluetooth (BT) connectivitystandard such as Bluetooth, Bluetooth 4.0 or Bluetooth 5.0, or any otheriteration of the Bluetooth Standard. In embodiments that include BTfunctionality as shown for example in FIG. 4, the radio architecture 400may be configured to establish a BT synchronous connection oriented(SCO) link and/or a BT low energy (BT LE) link. In some of theembodiments that include functionality, the radio architecture 400 maybe configured to establish an extended SCO (eSCO) link for BTcommunications, although the scope of the embodiments is not limited inthis respect. In some of these embodiments that include a BTfunctionality, the radio architecture may be configured to engage in aBT Asynchronous Connection-Less (ACL) communications, although the scopeof the embodiments is not limited in this respect. In some embodiments,as shown in FIG. 4, the functions of a BT radio card and WLAN radio cardmay be combined on a single wireless radio card, such as single wirelessradio card 402, although embodiments are not so limited, and includewithin their scope discrete WLAN and BT radio cards.

In some embodiments, the radio-architecture 400 may include other radiocards, such as a cellular radio card configured for cellular (e.g., 3GPPsuch as LTE, LTE-Advanced or 5G communications).

In some IEEE 802.11 embodiments, the radio architecture 400 may beconfigured for communication over various channel bandwidths includingbandwidths having center frequencies of about 900 MHz, 2.4 GHz, 5 GHz,and bandwidths of about 1 MHz, 2 MHz, 2.5 MHz, 4 MHz, 5 MHz, 8 MHz, 10MHz, 16 MHz, 20 MHz, 40 MHz, 80 MHz (with contiguous bandwidths) or80+80 MHz (160 MHz) (with non-contiguous bandwidths). In someembodiments, a 320 MHz channel bandwidth may be used. The scope of theembodiments is not limited with respect to the above center frequencieshowever.

FIG. 5 illustrates FEM circuitry 500 in accordance with someembodiments. The FEM circuitry 500 is one example of circuitry that maybe suitable for use as the WLAN and/or BT FEM circuitry 404A/404B (FIG.4), although other circuitry configurations may also be suitable.

In some embodiments, the FEM circuitry 500 may include a TX/RX switch502 to switch between transmit mode and receive mode operation. The FEMcircuitry 500 may include a receive signal path and a transmit signalpath. The receive signal path of the FEM circuitry 500 may include alow-noise amplifier (LNA) 506 to amplify received RF signals 503 andprovide the amplified received RF signals 507 as an output (e.g., to theradio IC circuitry 406 (FIG. 4)). The transmit signal path of thecircuitry 500 may include a power amplifier (PA) 510 to amplify input RFsignals 509 (e.g., provided by the radio IC circuitry 406), and one ormore filters 512, such as band-pass filters (BPFs), low-pass filters(LPFs) or other types of filters, to generate RF signals 515 forsubsequent transmission (e g., by one or more of the antennas 401 (FIG.4)).

In some dual-mode embodiments for Wi-Fi communication, the FEM circuitry500 may be configured to operate in either the 2.4 GHz frequencyspectrum or the 5 GHz frequency spectrum. In these embodiments, thereceive signal path of the FEM circuitry 500 may include a receivesignal path duplexer 504 to separate the signals from each spectrum aswell as provide a separate LNA 506 for each spectrum as shown. In theseembodiments, the transmit signal path of the FEM circuitry 500 may alsoinclude a power amplifier 510 and a filter 512, such as a BPF, a LPF oranother type of filter for each frequency spectrum and a transmit signalpath duplexer 514 to provide the signals of one of the differentspectrums onto a single transmit path for subsequent transmission by theone or more of the antennas 401 (FIG. 4). In some embodiments, BTcommunications may utilize the 2.4 GHZ signal paths and may utilize thesame FEM circuitry 500 as the one used for WLAN communications.

FIG. 6 illustrates radio IC circuitry 600 in accordance with someembodiments. The radio IC circuitry 600 is one example of circuitry thatmay be suitable for use as the WLAN or BT radio IC circuitry 406A/406B(FIG. 4), although other circuitry configurations may also be suitable.

In some embodiments, the radio IC circuitry 600 may include a receivesignal path and a transmit signal path. The receive signal path of theradio IC circuitry 600 may include at least mixer circuitry 602, suchas, for example, down-conversion mixer circuitry, amplifier circuitry606 and filter circuitry 608. The transmit signal path of the radio ICcircuitry 600 may include at least filter circuitry 612 and mixercircuitry 614, such as, for example, up-conversion mixer circuitry.Radio IC circuitry 600 may also include synthesizer circuitry 604 forsynthesizing a frequency 605 for use by the mixer circuitry 602 and themixer circuitry 614. The mixer circuitry 602 and/or 614 may each,according to some embodiments, be configured to provide directconversion functionality. The latter type of circuitry presents a muchsimpler architecture as compared with standard super-heterodyne mixercircuitries, and any flicker noise brought about by the same may bealleviated for example through the use of OFDM modulation. FIG. 6illustrates only a simplified version of a radio IC circuitry, and mayinclude, although not shown, embodiments where each of the depictedcircuitries may include more than one component. For instance, mixercircuitry 602 and/or 614 may each include one or more mixers, and filtercircuitries 608 and/or 612 may each include one or more filters, such asone or more BPFs and/or LPFs according to application needs. Forexample, when mixer circuitries are of the direct-conversion type, theymay each include two or more mixers.

In some embodiments, mixer circuitry 602 may be configured todown-convert RF signals 507 received from the FEM circuitry 404 (FIG. 4)based on the synthesized frequency 605 provided by synthesizer circuitry604. The amplifier circuitry 606 may be configured to amplify thedown-converted signals and the filter circuitry 608 may include a LPFconfigured to remove unwanted signals from the down-converted signals togenerate output baseband signals 607. Output baseband signals 607 may beprovided to the baseband processing circuitry 408 (FIG. 4) for furtherprocessing. In some embodiments, the output baseband signals 607 may bezero-frequency baseband signals, although this is not a requirement. Insome embodiments, mixer circuitry 602 may comprise passive mixers,although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 614 may be configured toup-convert input baseband signals 611 based on the synthesized frequency605 provided by the synthesizer circuitry 604 to generate RF outputsignals 509 for the FEM circuitry 404. The baseband signals 611 may beprovided by the baseband processing circuitry 408 and may be filtered byfilter circuitry 612. The filter circuitry 612 may include a LPF or aBPF, although the scope of the embodiments is not limited in thisrespect.

In some embodiments, the mixer circuitry 602 and the mixer circuitry 614may each include two or more mixers and may be arranged for quadraturedown-conversion and/or up-conversion respectively with the help ofsynthesizer 604. In some embodiments, the mixer circuitry 602 and themixer circuitry 614 may each include two or more mixers each configuredfor image rejection (e.g., Hartley image rejection). In someembodiments, the mixer circuitry 602 and the mixer circuitry 614 may bearranged for direct down-conversion and/or direct up-conversion,respectively. In some embodiments, the mixer circuitry 602 and the mixercircuitry 614 may be configured for super-heterodyne operation, althoughthis is not a requirement.

Mixer circuitry 602 may comprise, according to one embodiment:quadrature passive mixers (e.g., for the in-phase (I) and quadraturephase (Q) paths). In such an embodiment, RF input signal 507 from FIG. 6may be down-converted to provide I and Q baseband output signals to besent to the baseband processor.

Quadrature passive mixers may be driven by zero and ninety degreetime-varying LO switching signals provided by a quadrature circuitrywhich may be configured to receive a LO frequency (f_(LO)) from a localoscillator or a synthesizer, such as LO frequency 605 of synthesizer 604(FIG. 6). In some embodiments, the LO frequency may be the carrierfrequency, while in other embodiments, the LO frequency may be afraction of the carrier frequency (e g., one-half the carrier frequency,one-third the carrier frequency). In some embodiments, the zero andninety degree time-varying switching signals may be generated by thesynthesizer, although the scope of the embodiments is not limited inthis respect.

In some embodiments, the LO signals may differ in duty cycle (thepercentage of one period in which the LO signal is high) and/or offset(the difference between start points of the period). In someembodiments, the LO signals may have a 25% duty cycle and a 50% offset.In some embodiments, each branch of the mixer circuitry (e.g., thein-phase (I) and quadrature phase (Q) path) may operate at a 25% dutycycle, which may result in a significant reduction is power consumption.

The RF input signal 507 (FIG. 5) may comprise a balanced signal,although the scope of the embodiments is not limited in this respect.The I and Q baseband output signals may be provided to low-noseamplifier, such as amplifier circuitry 606 (FIG. 6) or to filtercircuitry 608 (FIG. 6).

In some embodiments, the output baseband signals 607 and the inputbaseband signals 611 may be analog baseband signals, although the scopeof the embodiments is not limited in this respect. In some alternateembodiments, the output baseband signals 607 and the input basebandsignals 611 may be digital baseband signals. In these alternateembodiments, the radio IC circuitry may include analog-to-digitalconverter (ADC) and digital-to-analog converter (DAC) circuitry.

In some dual-mode embodiments, a separate radio IC circuitry may beprovided for processing signals for each spectrum, or for otherspectrums not mentioned here, although the scope of the embodiments isnot limited in this respect.

In some embodiments, the synthesizer circuitry 604 may be a fractional-Nsynthesizer or a fractional N/N+1 synthesizer, although the scope of theembodiments is not limited in this respect as other types of frequencysynthesizers may be suitable. For example, synthesizer circuitry 604 maybe a delta-sigma synthesizer, a frequency multiplier, or a synthesizercomprising a phase-locked loop with a frequency divider. According tosome embodiments, the synthesizer circuitry 604 may include digitalsynthesizer circuitry. An advantage of using a digital synthesizercircuitry is that, although it may still include some analog components,its footprint may be scaled down much more than the footprint of ananalog synthesizer circuitry. In some embodiments, frequency input intosynthesizer circuitry 604 may be provided by a voltage controlledoscillator (VCO), although that is not a requirement. A divider controlinput may further be provided by either the baseband processingcircuitry 408 (FIG. 4) or the application processor 411 (FIG. 4)depending on the desired output frequency 605. In some embodiments, adivider control input (e.g., N) may be determined from a look-up table(e.g., within a Wi-Fi card) based on a channel number and a channelcenter frequency as determined or indicated by the application processor411.

In some embodiments, synthesizer circuitry 604 may be configured togenerate a carrier frequency as the output frequency 605, while in otherembodiments, the output frequency 605 may be a fraction of the carrierfrequency (e.g., one-half the carrier frequency, one-third the carrierfrequency). In some embodiments, the output frequency 605 may be a LOfrequency (f_(LO)).

FIG. 7 illustrates a functional block diagram of baseband processingcircuitry 700 in accordance with some embodiments. The basebandprocessing circuitry 700 is one example of circuitry that may besuitable for use as the baseband processing circuitry 408 (FIG. 4),although other circuitry configurations may also be suitable. Thebaseband processing circuitry 700 may include a receive basebandprocessor (RX BBP) 702 for processing receive baseband signals 609provided by the radio IC circuitry 406 (FIG. 4) and a transmit basebandprocessor (TX BBP) 704 for generating transmit baseband signals 611 forthe radio IC circuitry 406. The baseband processing circuitry 700 mayalso include control logic 706 for coordinating the operations of thebaseband processing circuitry 700.

In some embodiments (e.g., when analog baseband signals are exchangedbetween the baseband processing circuitry 700 and the radio IC circuitry406), the baseband processing circuitry 700 may include ADC 710 toconvert analog baseband signals received from the radio IC circuitry 406to digital baseband signals for processing by the RX BBP 702. In theseembodiments, the baseband processing circuitry 700 may also include DAC712 to convert digital baseband signals from the TX BBP 704 to analogbaseband signals.

In some embodiments that communicate OFDM signals or OFDMA signals, suchas through baseband processor 408A, the transmit baseband processor 704may be configured to generate OFDM or OFDMA signals as appropriate fortransmission by performing an inverse fast Fourier transform (IFFT). Thereceive baseband processor 702 may be configured to process receivedOFDM signals or OFDMA signals by performing an FFT. In some embodiments,the receive baseband processor 702 may be configured to detect thepresence of an OFDM signal or OFDMA signal by performing anautocorrelation, to detect a preamble, such as a short preamble, and byperforming a cross-correlation, to detect a long preamble. The preamblesmay be part of a predetermined frame structure for Wi-Fi communication.

Referring back to FIG. 4, in some embodiments, the antennas 401 (FIG. 4)may each comprise one or more directional or omnidirectional antennas,including, for example, dipole antennas, monopole antennas, patchantennas, loop antennas, microstrip antennas or other types of antennassuitable for transmission of RF signals. In some multiple-inputmultiple-output (MIMO) embodiments, the antennas may be effectivelyseparated to take advantage of spatial diversity and the differentchannel characteristics that may result. Antennas 401 may each include aset of phased-array antennas, although embodiments are not so limited.

Although the radio-architecture 400 is illustrated as having severalseparate functional elements, one or more of the functional elements maybe combined and may be implemented by combinations ofsoftware-configured elements, such as processing elements includingdigital signal processors (DSPs), and/or other hardware elements. Forexample, some elements may comprise one or more microprocessors, DSPs,field-programmable gate arrays (FPGAs), application specific integratedcircuits (ASICs), radio-frequency integrated circuits (RFICs) andcombinations of various hardware and logic circuitry for performing atleast the functions described herein. In some embodiments, thefunctional elements may refer to one or more processes operating on oneor more processing elements.

In accordance with some embodiments, the AP 102 may contend for atransmission opportunity (TXOP) to obtain access to a channel. The AP102 may transmit a trigger frame (TF) to initiate a multi-user (MU)location measurement during the TXOP. The AP 102 may receive servicerequests for the MU location measurement from a plurality of STAs 103.The service requests may be multiplexed in an orthogonal frequencydivision multiple access (OFDMA) signal. The AP 102 may transmit an MUacknowledgement (ACK) frame that indicates reception of the servicerequests. The AP 102 may receive, from the STAs 103, uplink soundingframes that include per-STA timing information for the service requestsand the MU ACK frame. The uplink sounding frames may be multiplexed inan OFDMA signal. The STA 103 may determine location measurements for theSTAs 103 based on the per-STA timing information included in the uplinksounding frames. These embodiments will be described in more detailbelow.

FIG. 8 illustrates the operation of a method of communication inaccordance with some embodiments. It is important to note thatembodiments of the method 800 may include additional or even feweroperations or processes in comparison to what is illustrated in FIG. 8.In addition, embodiments of the method 800 are not necessarily limitedto the chronological order that is shown in FIG. 8. In describing themethod 800, reference may be made to FIGS. 1-7 and 9-15, although it isunderstood that the method 800 may be practiced with any other suitablesystems, interfaces and components.

In some embodiments, the AP 102 and/or STA 103 may be configurable tooperate as an HE device 104. Although reference may be made to an AP 102and/or STA 103 herein, including as part of the descriptions of themethod 800 and/or other methods described herein, it is understood thatan HE device 104, an AP 102 configurable to operate as an HE device 104and/or STA 103 configurable to operate as an HE device 104 may be usedin some embodiments. In addition, the method 800 and other methodsdescribed herein may be applicable to STAs 103, HE devices 104 and/orAPs 102 operating in accordance with one or more standards and/orprotocols, such as 802.11, Wi-Fi, wireless local area network (WLAN)and/or other, but embodiments of those methods are not limited to justthose devices. In some embodiments, the method 800 and other methodsdescribed herein may be practiced by other mobile devices, such as anEvolved Node-B (eNB) or User Equipment (UE). The method 800 and othermethods described herein may also be practiced by wireless devicesconfigured to operate in other suitable types of wireless communicationsystems, including systems configured to operate according to variousThird Generation Partnership Project (3GPP) Long Term Evolution (LTE)standards. The method 800 may also be applicable to an apparatus for anSTA 103, HE device 104 and/or AP 102 or other device described above, insome embodiments.

It should also be noted that embodiments are not limited by referencesherein (such as in descriptions of the methods 800, 1100, 1200, 1500and/or other descriptions herein) to transmission, reception and/orexchanging of elements such as frames, messages, requests, indicators,signals or other elements. In some embodiments, such an element may begenerated, encoded or otherwise processed by processing circuitry (suchas by a baseband processor included in the processing circuitry) fortransmission. The transmission may be performed by a transceiver orother component, in some cases. In some embodiments, such an element maybe decoded, detected or otherwise processed by the processing circuitry(such as by the baseband processor). The element may be received by atransceiver or other component, in some cases. In some embodiments, theprocessing circuitry and the transceiver may be included in a sameapparatus. The scope of embodiments is not limited in this respect,however, as the transceiver may be separate from the apparatus thatcomprises the processing circuitry, in some embodiments.

In addition, although the method 800 may be described in terms ofoperations performed by an AP 102, such descriptions are not limiting.The method 800 may be practiced by an STA 103 and/or other device, insome embodiments.

At operation 805 of the method 800, the AP 102 may contend for atransmission opportunity (TXOP) to obtain access to a channel. In someembodiments, the AP 102 may contend for a TXOP during which the AP 102is to control access to the channel. In some embodiments, the AP 102 maycontend for a wireless medium during a contention period to receiveexclusive control of the medium during a period, including but notlimited to a TXOP and/or HE control period. The AP 102 may transmit,receive and/or schedule one or more frames and/or signals during theperiod. The AP 102 may transmit and/or receive one or more frames and/orsignals during the period. However, it should be noted that embodimentsare not limited to scheduled transmission/reception or totransmission/reception in accordance with the exclusive control of themedium. Accordingly, an MPDU, PPDU, BA frame and/or other frame may betransmitted/received in contention-based scenarios and/or otherscenarios, in some embodiments. Any suitable contention methods,operations and/or techniques may be used, which may or may not be partof a standard. In a non-limiting example, one or more contentionmethods, operations and/or techniques of an 802.11 standard/protocoland/or W-LAN standard/protocol may be used.

At operation 810, the AP 102 may transmit a trigger frame (TF). In someembodiments, the TF may be transmitted during the TXOP. In someembodiments, the TF may be transmitted to initiate a multi-user (MU)location measurement during the TXOP. In some embodiments, the MUlocation measurement may be configurable for location measurement of oneor more associated STAs 103. In some embodiments, the MU locationmeasurement may be configurable for location measurement of one or moreunassociated STAs 103. In some embodiments, the MU location measurementmay be configurable for location measurement of a combination ofassociated STA(s) 103 and unassociated STA(s) 103. As part of the MUlocation measurement, one or more location measurements for one or moreSTAs 103 may be determined. Such location measurements may be based ondistances between the AP 102 and the STAs 103, angles of arrival betweenthe AP 102 and the STAs 103, time-of-flight (ToF) between the AP 102 andthe STAs 103 and/or other.

In a non-limiting example, the TF may be a Trigger Frame Random AccessService Request (TFR SR), which may be a type of TF. In someembodiments, the TF may be a Random Access general TF, which may ask forany Service Random Access TF or dedicated TF for location service. Insome embodiments, the TF may be a non-Random Access TF that requestsSTAs 103 to transmit service requests if the STAs 103 wish to and/orneed to. In some embodiments, the TF may include a TF type parameter (orsimilar) that may indicate which type of TF is used. For instance, agroup of candidate TF types may include one or more of TFR SR, TFLocation (TFL) and/or other. It should be noted that embodiments are notlimited to usage of TFs that are of different types. For instance, theTF may not necessarily be characterized by a TF type, in someembodiments.

In some embodiments, the TF may indicate information to be used by theSTA 103 to exchange one or more frames and/or signals (such as thePPDUs) with the AP 102 during a transmission opportunity (TXOP). Exampleinformation of the TF may include, but is not limited to, time resourcesto be used for transmission and/or reception, channel resources (such asresource units (RUs) and/or other) to be used for transmission and/orreception, identifiers of STAs 103 that are to transmit, identifiers ofSTAs 103 that are to receive and/or other information. It should benoted that embodiments are not limited to usage of the TF, and someembodiments may not necessarily include the usage of the TF.

In a non-limiting example, the TF and/or TFR SR may indicate a specificallocation of RUs of the channel to be used by one or more of the STAs103 for transmission of service requests as part of an OFDMA signaland/or Random Access allocation of RUs. In another non-limiting example,the TF and/or TFR SR may indicate information related to uplinktransmission by associated STAs 103 or unassociated STAs 103 or acombination thereof. For instance, the TF and/or TFR SR may beconfigurable to allocate at least a first RU to a particular associatedSTA 103 for a service request from the particular associated STA 103,and the TFR SR may be further configurable to allocate at least a secondRU for contention based transmission of service requests by unassociatedSTAs 103. It should be noted that multiple STAs may be supported. Forinstance, the TF and/or TFR SR may allocate one or more RUs to each ofmultiple STAs for transmission of service request(s), in some cases.

At operation 815, the AP 102 may receive service requests for the MUlocation measurement from one or more STAs 103. In some embodiments, theservice requests may be received during the TXOP, although the scope ofembodiments is not limited in this respect. In some embodiments, theSTAs 103 from which the service requests are received may be indicatedby the TF of operation 810. One or more of the STAs 103 may beunassociated STAs 103, in some cases. The one or more STAs 103 mayinclude one or more associated STAs 103, one or more unassociated STAsor a combination thereof.

In some embodiments, the AP 102 may receive the service requests for theMU location measurement from a plurality of STAs 103. The servicerequests may be multiplexed in an OFDMA signal, in some cases. In someembodiments, uplink multi-user multiple-input multiple-output (MU-MIMO)techniques and/or combination may be used for transmission of theservice requests by the STAs 103.

At operation 820, the AP 102 may transmit an MU ACK frame and/orbroadcast multi STAs ACK that indicates reception of the servicerequest(s). In some embodiments, the MU ACK frame may be transmittedduring the TXOP, although the scope of embodiments is not limited inthis respect. The MU ACK frame may be transmitted as part of an OFDMAsignal. OFDM signal and/or any suitable type of signal. In someembodiments, the MU ACK frame may include broadcast multi-STA ACKoption.

At operation 825, the AP 102 may transmit a TF to schedule uplinksounding frame(s) from one or more STAs 103 and/or downlink soundingframe(s) from one or more STAs 103. In some embodiments, the TFtransmitted at operation 825 may be transmitted during the TXOP,although the scope of embodiments is not limited in this respect. In anon-limiting example, the TF transmitted at operation 810 may be a firstTF and the TF transmitted at operation 825 may be a second TF that istransmitted after the first TF. In some cases, the second TF may betransmitted after transmission of the MU ACK frame, although the scopeof embodiments is not limited in this respect. In some embodiments, thesecond TF may be a TF Location (TFL) For instance, a TF type parameterincluded in the second TF may indicate that the second TF is a TFL. Itshould be noted that embodiments are not limited to usage of a TF typefor either the first TF or the second TF.

At operation 830, the AP 102 may receive one or more uplink soundingframes from one or more STAs 103. In some embodiments, the uplinksounding frames may be received during the TXOP, although the scope ofembodiments is not limited in this respect. In some embodiments, theuplink sounding frames may be multiplexed in an OFDMA signal, althoughthe scope of embodiments is not limited in this respect. For instance,MU-MIMO techniques may be used by the STAs 103 for transmission of theuplink sounding frames, in some cases.

In a non-limiting example, the uplink sounding frames may includeper-STA timing information for the service requests and the MU ACKframe. For instance, the sounding frame from a particular STA 103 mayinclude timing information that is based at least partly on atransmission time of the service request from the particular STA 103and/or a reception time of the MU ACK frame at the particular STA 103.As an example, the transmission time of the service request from theparticular STA 103 and/or the reception time of the MU ACK frame at theparticular STA 103 may be included in the uplink sounding frame from theparticular STA 103. As another example, a difference between thereception time of the MU ACK frame at the particular STA 103 and thetransmission time of the service request from the particular STA 103 maybe included in the uplink sounding frame from the particular STA 103.These examples are not limiting, however, as other timing informationmay be included in the uplink sounding frame from the particular STA103. Any suitable unit (such as microseconds, milliseconds, and/orother) may be used for the transmission time, reception time and/ordifference between times. In some embodiments, a suitable reference time(such as a system reference time, a reference time of the STA 103, areference time of the AP 102 and/or other) may be used to indicate thetransmission time, reception time and/or difference between times.

In some embodiments, uplink sounding frames may include uplink locationmeasurement reports (LMRs) that may include the per-STA timinginformation. Embodiments are not limited to usage of LMRs, however, asother elements within the uplink sounding frames may be include theper-STA timing information, in some cases. In addition, such per-STAtiming information may be included directly in the uplink soundingframes in some cases.

In some embodiments, sounding waveforms may be included in the uplinksounding frames. The uplink sounding waveforms may include trainingsymbols, in some cases. Accordingly, channel state information (CSI) maybe determined at the AP 102 (such as at operation 840) based on theuplink sounding waveform(s), in some embodiments. The CSI may bedetermined per-STA, in some embodiments. For instance, the AP 102 maydetermine uplink CSI for a particular STA 103 based on an uplinksounding waveform included in an uplink sounding frame from theparticular STA 103. This determination may be extended to multiple STAs103, in some cases.

In some embodiments, the AP 102 may perform power control for the uplinksounding frames for one or more of the STAs 103 from which the soundingframe(s) are received. In a non-limiting example, a transmit power to beused by a particular STA 103 for transmission of an uplink soundingwaveform may be determined based at least partly on a previouslyreceived uplink frame from the particular STA 103. Accordingly, the AP102 may determine such a transmit power for each of multiple STAs 103,in some cases. In some embodiments, closed loop power control may beused, although the scope of embodiments is not limited in this respect.In some embodiments, the AP 102 may communicate transmit power(s) to oneor more STA 103 in any suitable frame and/or message.

At operation 835, the AP 102 may determine location information for theplurality of STAs 103. In some embodiments, the location information maybe determined based at least partly on information included in theuplink sounding frame. For instance, per-STA timing information may beused to determine location information for the STAs 103. Accordingly,location information of multiple STAs 103 may be determined, in somecases.

In some embodiments, a location measurement for a particular STA 103 maybe based at least partly on one or more values, such as a transmissiontime of the service request from the particular STA 103, a receptiontime (at the AP 102) of the service request from the particular STA 103,a transmission time (at the AP 102) of the MU ACK frame, a receptiontime of the MU ACK frame at the particular STA 103 and/or other time. Insome cases, one or more differences, summations and/or othercombinations of such values may be used.

In a non-limiting example, a time-of-flight (ToF) measurement may bedetermined. The ToF measurement may be based on a first differencebetween the reception time of the MU ACK frame at the particular STA 103and the transmission time of the service request from the particular STA103. The ToF measurement may be further based on a second differencebetween the transmission time (at the AP 102) of the MU ACK frame andthe reception time (at the AP 102) of the service request from theparticular STA 103. The ToF measurement may be determined as one half ofa difference between the first difference and the second difference. Inaddition, a range estimate of the particular STA 103 may be determinedusing the ToF measurement and the speed of light. For instance, therange estimate may be (or may be based on) the ToF measurementmultiplied by the speed of light.

At operation 845, the AP 102 may transmit one or more downlink soundingframes. In some embodiments, the downlink sounding frames may betransmitted during the TXOP, although the scope of embodiments is notlimited in this respect. The downlink sounding frames may be multiplexedin a third OFDMA signal, in some cases. In some embodiments, thedownlink sounding frames may include the determined locationmeasurements for the STAs 103 and/or the per-STA CSI. Downlink LMRs maybe used, in some cases, although the scope of embodiments is not limitedin this respect. In some embodiments, the downlink sounding frames mayfurther include downlink sounding waveforms, which may be used by theSTAs 103 for determination of CSI in the downlink direction.

In some embodiments, the AP 102 may determine modulation and codingschemes (MCSs) to be used by the STAs 103. The MCSs may be determinedbased at least partly on the timing information described previously,the determined location measurement(s) and/or other information. Forinstance, for the STAs 103 from which the service requests are received(or at least a portion of those STAs 103), an MCS may be determined foreach STA 103. The MCSs may be communicated to the STAs 103 using anysuitable message.

FIG. 9 illustrates example operations in accordance with someembodiments. FIG. 10 illustrates example frames in accordance with someembodiments. It should be noted that the examples shown in FIGS. 9-10may illustrate some or all of the concepts and techniques describedherein in some cases, but embodiments are not limited by the examples ofFIGS. 9-10. For instance, embodiments are not limited by the name,number, type, size, ordering, arrangement and/or other aspects of theframes, signals, fields, data blocks, operations, time resources andother elements as shown in FIGS. 9-10. Although some of the elementsshown in the examples of FIGS. 9-10 may be included in an 802.11standard and/or other standard, embodiments are not limited to usage ofsuch elements that are included in standards.

Referring to FIG. 9, at operation 912, the AP 102 may transmit a TFR SR.At operation 914, the STA 103 may transmit a service request forlocation. At operation 916, the AP 102 may transmit an ACK MU frame.Operations 912-916 may be performed during a service negotiation phase910, in some cases, although embodiments are not limited to usage of aphase. At operation 922, the AP 102 may transmit a TF location. Atoperation 924, the STA 103 may transmit an uplink sounding frame thatmay include an uplink LMR (with timing information). At operation 926,the AP 102 may transmit downlink sounding frames that may includedownlink LMRs. Location information, uplink CSI and/or other informationmay be included. Operations 922-926 may be performed during ameasurement exchange phase 920, in some cases, although embodiments arenot limited to usage of a phase.

Referring to FIG. 10, example frames are shown. The AP 102 may transmita TFR SR 1012. The STAs 103 may transmit service requests for locationin an OFDMA signal. Any suitable number of STAs 103 (such as anysuitable value for the variable “n”) may be used. The AP 102 maytransmit an ACK MU frame 1016. The frames 1012-1016 may be exchangedduring a service negotiation phase 1010, in some cases, althoughembodiments are not limited to usage of a phase. The AP 102 may transmita TF location 1022. The STAs 103 may transmit uplink sounding frames1024. In some cases, the uplink sounding frames may include data (suchas uplink LMRs, timing information and/or other) and may further includesounding waveforms. In some cases, OFDMA may be used for transmission ofthe uplink sounding frames. The AP 102 may transmit downlink soundingframes 1026. Location information, uplink CSI and/or other informationmay be included. In some cases, OFDMA may be used for transmission ofthe downlink sounding frames. The frames 1022-1026 may be exchangedduring a measurement exchange phase 1020, in some cases, althoughembodiments are not limited to usage of a phase.

In the previous non-limiting example, the time-of-flight (ToF)measurement may be illustrated using FIG. 9. The ToF measurement may bebased on a first difference (t4−t1) between the reception time (t4) ofthe MU ACK frame at the particular STA 103 and the transmission time(t1) of the service request from the particular STA 103. The ToFmeasurement may be further based on a second difference (t3−t2) betweenthe transmission time (t3) of the MU ACK frame at the AP 102 and thereception time (t2) of the service request from the particular STA 103at the AP 102. The ToF measurement may be determined as(½)*((t4−t1)−(t3−t2)).

It should be noted that in the above example, the STA 103 may providethe AP 102 with t1 and t4 (and/or the difference (t4−t1)), and thevalues of t2 and t3 may be known (and/or determinable) at the AP 102.

In some embodiments, a scheduled operation mode may be used. In anon-limiting example, a simultaneous multi-user transmission andreception mode may be used, in which an AP 102 may control resourceallocation assignment. For instance, the assigned client STA 103,bandwidth, modulation and coding scheme (MCS), transmission time and/orother parameters may be allocated and/or specified by the AP 102. Such amode may be included in an 802.11 standard and/or other standard,although embodiments are not limited to usage of modes included in astandard.

In some embodiments, a scheduled location (and/or position) measurementand signaling techniques may be used. In some of those embodiments, thetechniques may be applicable to associated and unassociated MUoperation. In some embodiments, trigger based location (and/or position)measurement and signaling may be used. In some cases, multiple phasesmay be used, although the scope of embodiments is not limited to usageof different phases. For instance, a service negotiation phase and alocation measurement exchange phase may be used.

In some embodiments, concurrent fine timing measurements (FTM) frommultiple STAs (associated and unassociated) may be performed viaenabling multiple concurrent negotiation and measurements to take placein a single TXOP. In some embodiments, scheduled location (and/orposition) measurements may be supported. For instance, an 802.11ax MUmode may be used. When the 802.11ax MU mode is used, an STA 103 in theunassociated or legacy mode may have a much lower probability ofobtaining the medium. For instance, venues in which an indoor locationis used (such as malls, stadia, large event sites and/or other) may usethe 802.11ax MU mode, in some cases.

In some embodiments, reciprocal (and/or symmetrical) measurement may beenabled by techniques described herein. A full band preamble for UL andDL may be used (for instance, unlike other techniques in which DLmeasurements may be limited to legacy non-HT duplicate frames). In somecases, higher accuracy may be enabled, due to improved channelresolution (such as a “DL sounding plus LMR” part shown in various FIGS.herein).

In some embodiments, techniques described herein may enable bothmeasurement and measurement results to be conveyed using a single frame(such as the “data plus sounding” transmission/reception shown invarious FIGS. herein). In some cases, this may result in an efficientuse of the medium (channel) and power.

In some embodiments, techniques described herein may enable an AP 102and/or STA 103 to provide location measurement results in a same “DLSounding plus LMR” part at least partly due to the “UL Sounding plusLMR” part preceding the “DL Sounding plus LMR” part (such as in a“location measurement exchange phase” shown in various FIGS. herein).

In some embodiments, channel state information (CSI) may be provided toa client (such as a client STA 103 or AP 102). Accordingly, the clientmay be enabled to make location measurements (such as “Time Of Arrivaland/or other) for both directions. Thus, lower computational load at theAP 102 may be enabled.

In some embodiments, techniques described herein may enable a moreefficient use of the medium in comparison to other techniques (such asREV me FTM and/or other) by enabling division of the BW to distributemultiple client STAs 103 over the frequency domain. For instance, afirst STA 103 may use an upper 40 Mhz and a second STA 103 may use alower 40 MHz part.

In some embodiments, measurements may include one or more of range,distance, angle (azimuth and/or elevation) and/or other measurement. Forinstance, signaling in the Service Request may be used. In some cases, asame measurement frame may be used.

Referring to FIGS. 9-10, during the negotiation phase, the STA(s) 103may randomly select an RU from a Trigger frame for random access or ascheduled RU in the Trigger frame. The STAs 103 may either send an SRfor location measurement or any other short (control or data) frames(including but not limited to frames defined in 802.11ax).

In FIG. 10, the STAs 103 send SRs as solicited by a Trigger frame forrandom access. The timing starts with a TFR SR (Trigger Frame RandomAccess Service Request), which is used to enable assignment of ULresources to client STAs 103 to allow, permit and/or enable bothassociated and unassociated STAs 103 to make location/positioningmeasurement requests. This may be done using a collision channel in oneof several methods. For instance, the use of this collision allocationmay be extended to unassociated operation, in some cases. The TFR mayallocate a time/frequency segment to make an SR of type Location and maydefine an MCS (such as an MCS requirement, recommended MCS and/or MCS tobe used) of each segment. STAs 103 may choose one of the segmentsrandomly to make an SR of type Location and may provide their identity.The ACK (MU) may indicate which attempts were successfully received bythe AP 102. The second phase is the Location Measurement Exchange phase.This phase may be composed of two parts (such as an “UL sounding plusLMR” part and a “DL sounding plus LMR” part in this example), althoughembodiments are not limited to two parts or even to usage of parts. The“UL sounding plus LMR” part may precede the “DL sounding plus LMR” part,in some cases, such that the measurement results of the former part (UL)are available for reporting during the latter part (DL). In the “ULsounding plus LMR” part, the Trigger Frame (TF) may be a TF Location(TFL), which may allocate resources and may time synchronize the MU forUL transmission. In the “DL sounding plus LMR” part, the AP 102 mayrespond with one or more DL measurement frames (Sounding plus LMR) tothe client STAs 103. In some embodiments, the response may also includethe measured channel state information (CSI) based on the ULmeasurement.

FIG. 11 illustrates the operation of another method of communication inaccordance with some embodiments. As mentioned previously regarding themethod 800, embodiments of the method 1100 may include additional oreven fewer operations or processes in comparison to what is illustratedin FIG. 11 and embodiments of the method 1100 are not necessarilylimited to the chronological order that is shown in FIG. 11. Indescribing the method 1100, reference may be made to FIGS. 1-10 and12-15, although it is understood that the method 1100 may be practicedwith any other suitable systems, interfaces and components.

In some embodiments, the STA 103 may be configurable to operate as an HEdevice 104. Although reference may be made to an STA 103 herein,including as part of the descriptions of the method 1100 and/or othermethods described herein, it is understood that an HE device 104 and/orSTA 103 configurable to operate as an HE device 104 may be used in someembodiments. In addition, embodiments of the method 800 may beapplicable to APs 102, STAs 103, UEs, eNBs or other wireless or mobiledevices. The method 1100 may also be applicable to an apparatus for anAP 102, STA 103 and/or other device described above.

It should be noted that the method 800 may be practiced by an AP 102 andmay include exchanging of elements, such as frames, signals, messages,fields and/or other elements, with an STA 103. Similarly, the method1100 may be practiced at an STA 103 and may include exchanging of suchelements with an AP 102. In some cases, operations and techniquesdescribed as part of the method 800 may be relevant to the method 1100.In addition, embodiments of the method 1100 may include operationsperformed at the STA 103 that are reciprocal to or similar to otheroperations described herein performed at the AP 102. For instance, anoperation of the method 1100 may include reception of a frame from theAP 102 by the STA 103 while an operation of the method 800 may includetransmission of the same frame or similar frame by the AP 102.

In addition, previous discussion of various techniques and concepts maybe applicable to the method 1100 in some cases, including contentionbased access. TXOPs, trigger frames (TFs), TFR SR, TFL, MU locationmeasurement, location measurements, service request, MU ACK frame,uplink sounding frames, uplink sounding waveforms, uplink LMRs, downlinksounding frames, downlink sounding waveforms, downlink LMRs. CSI, ToFmeasurements and/or others. In addition, one or more of the examplesshown in FIGS. 9-10 may also be applicable, in some cases, although thescope of embodiments is not limited in this respect.

At operation 1105, the STA 103 may receive a trigger frame (TF) receivedduring a transmission opportunity (TXOP) obtained by an AP 102. Atoperation 1110, the STA 103 may transmit, in response to the TF, aservice request for a location measurement of the STA 103 as part of amulti-user (MU) location measurement by the AP 102. In some embodiments,the service request may be multiplexed in an OFDMA signal. One or moreRUs indicated by the TF received at operation 1105 may be used by theSTA 103 for the service request. At operation 1115, the STA 103 mayreceive an MU ACK frame that indicates reception of the service request.At operation 1120, the STA 103 may receive a TF that indicates (and/orschedules) uplink sounding frame(s) and downlink sounding frame(s). Atoperation 1125, the STA 103 may transmit an uplink sounding frame thatincludes timing information based at least partly on a transmission timeof the service request and a reception time of the MU ACK frame. In someembodiments, the uplink sounding frame may be multiplexed in an OFDMAsignal. One or more RUs indicated by the TF received at operation 1120may be used by the STA 103 for the uplink sounding frame. At operation1130, the STA 103 may receive a downlink sounding frame that includesthe location measurement for the STA 103. The location measurement maybe based on the timing information included in the uplink soundingframe. In some embodiments, the downlink sounding frame may bemultiplexed in an OFDMA signal. In some embodiments, some or all ofoperations 1105-1130 may be performed during the TXOP.

FIG. 12 illustrates the operation of another method of communication inaccordance with some embodiments. FIG. 13 illustrates additional exampleoperations in accordance with some embodiments. FIG. 14 illustratesadditional example frames in accordance with some embodiments. FIG. 15illustrates the operation of another method of communication inaccordance with some embodiments. As mentioned previously regarding themethod 800, embodiments of the methods 1200 and/or 1500 may includeadditional or even fewer operations or processes in comparison to whatis illustrated in FIGS. 12 and/or 15 and embodiments of the method 1200and/or 1500 are not necessarily limited to the chronological order thatis shown in FIGS. 12 and/or 15. In describing the method 1100, referencemay be made to any of FIGS. 1-15, although it is understood that themethods 1200 and/or 1500 may be practiced with any other suitablesystems, interfaces and components. Embodiments of the methods 1200and/or 1500 may be applicable to APs 102. STAs 103, UEs, eNBs or otherwireless or mobile devices. The methods 1200 and/or 1500 may also beapplicable to an apparatus for an AP 102, STA 103 and/or other devicedescribed above. It should be noted that the method 1200 may bepracticed by an AP 102 and may include exchanging of elements, such asframes, signals, messages, fields and/or other elements, with an STA103. Similarly, the method 1500 may be practiced at an STA 103 and mayinclude exchanging of such elements with an AP 102. In some cases,operations and techniques described as part of the method 1200 may berelevant to the method 1500. In addition, embodiments of the method 1500may include operations performed at the STA 103 that are reciprocal toor similar to other operations described herein performed at the AP 102.For instance, an operation of the method 1500 may include reception of aframe from the AP 102 by the STA 103 while an operation of the method1200 may include transmission of the same frame or similar frame by theAP 102. In addition, previous discussion of various techniques andconcepts may be applicable to the methods 1200 and/or 1500 in somecases, including contention based access, TXOPs, trigger frames (TFs).TFR SR, TFL. MU location measurement, location measurements, servicerequest, MU ACK frame, uplink sounding frames, uplink soundingwaveforms, uplink LMRs, downlink sounding frames, downlink soundingwaveforms, downlink LMRs, CSI, ToF measurements and/or others. One ormore operations of the methods 1200 and/or 1500 may be similar to,related to, reciprocal to and/or otherwise related to one or moreoperations of the methods 800 and/or 1100, although the scope ofembodiments is not limited in this respect. In addition, one or more ofthe examples shown in FIGS. 13-14 may also be applicable, in some cases,although the scope of embodiments is not limited in this respect.

It should be noted that the examples shown in FIGS. 13-14 may illustratesome or all of the concepts and techniques described herein in somecases, but embodiments are not limited by the examples of FIGS. 13-14.For instance, embodiments are not limited by the name, number, type,size, ordering, arrangement and/or other aspects of the frames, signals,fields, data blocks, operations, time resources and other elements asshown in FIGS. 13-14. Although some of the elements shown in theexamples of FIGS. 13-14 may be included in an 802.11 standard and/orother standard, embodiments are not limited to usage of such elementsthat are included in standards.

At operation 1205, the AP 102 may contend for a transmission opportunity(TXOP) to obtain access to a channel. At operation 1210, the AP 102 maytransmit a trigger frame (TF) to indicate that a plurality of STAs 103are to transmit uplink sounding frames during the TXOP. In someembodiments, the TF transmitted at operation 1210 may be a Trigger FrameRandom Access Service Request (TFR SR). In some cases, a TF typeparameter included in the TF transmitted at operation 1210 may indicatea TF type from a group of candidate TF types that includes one or moreof a TFR SR, TFL and/or other TF type.

At operation 1215, the AP 102 may receive service requests from one ormore STAs 103. In some embodiments, the service requests may be receivedin an OFDMA signal. In some embodiments, the service requests may bereceived in response to the TF of operation 1205. At operation 1220, theAP 102 may transmit an MU ACK frame that indicates reception of theservice requests.

At operation 1225, the AP 102 may transmit a TF to schedule uplinksounding frame(s) and/or downlink sounding frame(s). At operation 1230,the AP 102 may receive uplink sounding frames multiplexed in an OFDMAsignal received during the TXOP. In some embodiments, the uplinksounding frame(s) may comprise training symbols for uplink channel stateinformation (CSI) estimation. At operation 1235, the AP 102 maytransmit, during the TXOP, downlink sounding frame(s) multiplexed in anOFDMA signal. In some embodiments, the downlink sounding frame(s) maycomprise training symbols for downlink CSI estimation.

At operation 1240, the AP 102 may transmit a TF to schedule uplinkLMR(s) and/or downlink LMR(s). In some embodiments, the TF transmittedat operation 1240 may be a Trigger Frame for Location (TFL). In somecases, a TF type parameter included in the TF transmitted at operation1240 may indicate a TF type from a group of candidate TF types thatincludes one or more of a TFR SR, TFL and/or other TF type. At operation1245, the AP 102 may receive uplink LMRs multiplexed in an OFDMA signalreceived during the TXOP. In some embodiments, the uplink LMRs mayinclude per-STA timing information for the uplink sounding frames andthe downlink sounding frames. In a non-limiting example, the per-STAtiming information of a particular STA 103 of the plurality may be basedon one or more of, a transmission time of the uplink sounding frame fromthe particular STA 103; a reception time of the downlink sounding framefor the particular STA 103 at the particular STA 103; a differencebetween the transmission time of the uplink sounding frame from theparticular STA 103 and the reception time of the downlink sounding framefor the particular STA 103 at the particular STA 103; and/or otherinformation. It should be noted that the transmission of the uplink LMRsby one or more STAs 103 may be optional, in some embodiments.Accordingly, in some embodiments, the AP 102 may not necessarily receivethe uplink LMRs.

At operation 1250, the AP 102 may determine location measurements forthe STAs 103 based at least partly on the per-STA timing informationincluded in the uplink LMRs. In some embodiments, the locationmeasurement(s) may be or may be based on distances between the AP 102and the STAs 103, ToF between the AP 102 and the STAs 103, angles ofarrival between the AP 102 and the STAs 103 and/or other suitablemeasurements.

In a non-limiting example, a time-of-flight (ToF) measurement for aparticular STA 103 may be determined. The ToF measurement of theparticular STA 103 may be based on a first difference between thereception time of the downlink sounding frame for the particular STA 103at the particular STA 103 and the transmission time of the uplinksounding frame from the particular STA 103. The ToF measurement of theparticular STA 103 may be further based on a difference between atransmission time, at the AP 102, of the downlink sounding frame for theparticular STA 103 and a reception time, at the AP 102, of the uplinksounding frame from the particular STA 103. For instance, The ToFmeasurement may be determined as one half of a difference between thefirst difference and the second difference. In addition, a rangeestimate of the particular STA 103 may be determined using the ToFmeasurement and the speed of light. For instance, the range estimate maybe (or may be based on) the ToF measurement multiplied by the speed oflight. It should be noted that one or more measurements such aslocation, timing, ToF and/or other, may be determined by the AP 102, insome embodiments. In some embodiments, the STA 103 may determine one ormore such measurements. In some embodiments, the AP 102 may determineone or more such measurements and the STA 103 may determine one or moresuch measurements.

At operation 1255, the AP 102 may determine uplink CSI measurements. Insome embodiments, uplink sounding waveforms included in the uplinksounding frames may be used for this operation. Some embodiments may notnecessarily include operation 1255. At operation 1260, the AP 102 maytransmit downlink LMRs multiplexed in an OFDMA signal. In someembodiments, the downlink LMRs may include the location measurements. Insome embodiments, the downlink LMRs may include the uplink CSImeasurements.

In some embodiments, some or all frames transmitted and/or received inoperations 1210-1260 may be transmitted and/or received during the TXOP,although the scope of embodiments is not limited in this respect.

Referring to FIG. 13, at operation 1312, the AP 102 may transmit a TFRSR. At operation 1314, the STA 103 may transmit a service request forlocation. At operation 1316, the AP 102 may transmit an ACK MU frame.Operations 1312-1316 may be performed during a service negotiation phase1310, in some cases, although embodiments are not limited to usage of aphase. At operation 1322, the AP 102 may transmit a TF. At operation1324, the STA 103 may transmit an uplink sounding frame. At operation1326, the AP 102 may transmit downlink sounding frames. At operation1328, the AP may transmit a TF. At operation 1330, the STA may transmituplink LMRs. The uplink LMRs may include timing information, in somecases. At operation 1332, the AP 102 may transmit downlink LMRs.Location information, uplink CSI and/or other information may beincluded in the downlink LMRs, in some cases. Operations 1322-1332 maybe performed during a measurement exchange phase 1320, in some cases,although embodiments are not limited to usage of a phase.

Referring to FIG. 14, example frames are shown. One or more frames of aservice negotiation phase 1410 may be exchanged, including but notlimited to a TF, service requests, MU ACK and/or other. The AP 102 maytransmit a TF 1432. The STAs 103 may transmit uplink sounding frames1434. Any suitable number of STAs 103 (such as any suitable value forthe variable “n”) may be used. The AP 102 may transmit a downlinksounding waveforms 1436. The AP 102 may transmit a TF 1452. The STAs 103may transmit uplink LMRs 1454. The AP 102 may transmit downlink LMRs1456.

In the previous non-limiting example, the time-of-flight (ToF)measurement may be illustrated using FIG. 13. The ToF measurement may bebased on a first difference (t4−t1) between the reception time (t4) ofthe downlink sounding frame the particular STA 103 and the transmissiontime (t1) of the uplink sounding frame from the particular STA 103. TheToF measurement may be further based on a second difference (t3−t2)between the transmission time (t3) of the downlink sounding frame at theAP 102 and the reception time (t2) of the uplink sounding frame from theparticular STA 103 at the AP 102. The ToF measurement may be determinedas (½)*((t4−t1)−(t3−t2)).

It should be noted that in the above example, the STA 103 may providethe AP 102 with t1 and t4 (and/or the difference (t4−t1)), and thevalues of t2 and t3 may be known (and/or determinable) at the AP 102.

In some embodiments, a trigger frame (TF) based location (and/orposition) measurement and signaling may be used. Such measurement andsignaling may be divided into two phases, in some cases, such as aservice negotiation phase and a location measurement exchange phase(such as shown in FIGS. 13-14). Embodiments are not limited to twophases, to these particular phases or to usage of phases. Accordingly,operation(s) may be performed, in some embodiments, without thoseoperations being part of a phase. FIGS. 13-14 describe an examplemessage flow. The AP 102 may transmit a TF (for associated STAs 103) ora TFR (for both associated and unassociated STAs 103) allowing the STA103 to make a Service Request of type Location followed byacknowledgment by the AP 102 indicating correct reception of the requestfor one or more STAs 103. The service negotiation directs the STA 103 tothe time at which the measurement exchange will commence. After theservice negotiation, the AP 102 may assign the resource(s) to STAs 103to send and receive an UL and a DL measurement frame (UL and DLsounding), followed by a TF allocating resources for UL and DL LocationMeasurement Reporting (UL LMR and DL LMR). In some cases, the entireexchange may happen in a single TxOP (or part of a TxOP) such that theoverall on-channel time may be reduced and/or minimized.

In some embodiments, techniques described herein may enable concurrentFTM measurement from multiple STAs 103 by sending a simultaneoussounding measurement frame and/or Location Measurement Report (LMR). Insome embodiments, one or more operations (such as shown in FIGS. 13-14and/or other FIGS.) may be performed in accordance with an 802.11ax MUmode. The scope of embodiments is not limited in this respect, however,as one or more operations shown in FIGS. 13-14 may be performed in amode other than the 802.11ax MU mode. The operations may be performedwithout usage of a mode, in some embodiments.

FIG. 14 provides a timing of a location measurement procedure (forinstance, range and/or angle measurements) under the 802.11ax MU mode.Referring to FIGS. 13-14, any suitable operations may be used in thenegotiation phase. In a non-limiting example, one or more techniquesincluded in an 802.11 standard may be used. For instance, allocation ofRUs may include a pre-scheduled allocation or an allocation resultingfrom use of the Random Access (RA) allocation in which STAs 103 mayrandomly select an RU from a set described by a Trigger frame for randomaccess or a scheduled RU in a Trigger frame. In a non-limiting example,the STA 103 may either send a Service Request (SR) for locationmeasurement. In another non-limiting example, the STA 103 may sendanother type of frame and/or message. For instance, a short (control ordata) frame included in an 802.11ax standard and/or other standard.

In some embodiments, the measurement exchange part may include part(s)for one or more of the following: UL sounding, DL sounding, LMRreporting from AP 102 to STA 103. LMR reporting from STA 103 to AP 102and/or other. In some embodiments, the UL sounding part may start with aTF allocating UL timing and resources to one or more STAs 103 followedby an UL sounding followed by a DL sounding part. After the soundingpart, a second TF may be transmitted allocating UL resources and timingfor the LMR reporting from AP 102 to STA 103 followed by LMR reportingfrom STA 103 to AP 102. In some embodiments, the response may alsoinclude the measured channel state information (CSI) based on the ULmeasurement.

Referring to FIG. 15, at operation 1505 of the method 1500, the STA 103may receive a TF that indicates that a plurality of STAs 103 are totransmit uplink sounding frames during a transmission opportunity (TXOP)obtained by an AP 102. At operation 1510, the STA 103 may transmit aservice request for a location measurement in response to the TFreceived at operation 1510. The service request may be multiplexed in anOFDMA signal, in some embodiments. The STA 103 may receive an MU ACKframe that indicates reception of the service request at operation 1515.

At operation 1520, the STA 103 may receive, during the TXOP, a TF thatschedules uplink sounding frames and downlink sounding frame. Atoperation 1525, the STA 103 may transmit, during the TXOP, an uplinksounding frame multiplexed in an OFDMA signal. The uplink sounding framemay comprise training symbols for uplink channel state information (CSI)estimation, in some embodiments. At operation 1530, the STA 103 mayreceive a downlink sounding frame. The downlink sounding frame maycomprise training symbols for downlink CSI estimation, in someembodiments. The downlink sounding frame may be multiplexed in an OFDMAsignal received during the TXOP, in some embodiments.

At operation 1535, the STA 103 may receive, during the TXOP, a TF thatschedules uplink LMR(s) and downlink LMR(s). At operation 1540, the STA103 may transmit, during the TXOP, an uplink LMR. The uplink LMR mayinclude timing information for the transmission of the uplink soundingframe and the downlink sounding frames, in some embodiments. Forinstance, previously described timing information may be included. Atoperation 1545, the STA 103 may receive a downlink LMR during the TXOP.In some embodiments, the downlink LMR may include a location measurementfor the STA 103 based at least partly on the timing information includedin the uplink LMR.

It should be noted that embodiments are not limited to the operations,phases, frames, signals and/or other elements shown in the FIGS. 8-15.Some embodiments may not necessarily include all operations, phases,frames, signals and/or other elements shown. Some embodiments mayinclude one or more additional operations, phases, frames, signalsand/or other elements. One or more operations may be optional, in someembodiments. For instance, in FIG. 9, one or more of the operationsindicated by 912, 914, 916, 922, 924, 926 may not necessarily beincluded, in some embodiments.

In Example 1, an apparatus of an access point (AP) may comprise memory.The apparatus may further comprise processing circuitry. The processingcircuitry may be configured to contend for a transmission opportunity(TXOP) to obtain access to a channel. The processing circuitry may befurther configured to encode, for transmission during the TXOP, atrigger frame (TF) to indicate that a plurality of stations (STAs) areto transmit uplink sounding frames. The processing circuitry may befurther configured to decode the uplink sounding frames multiplexed in afirst orthogonal frequency division multiple access (OFDMA) signalreceived during the TXOP. The processing circuitry may be furtherconfigured to encode, for transmission during the TXOP, downlinksounding frames multiplexed in a second OFDMA signal. The processingcircuitry may be further configured to decode uplink locationmeasurement reports (LMRs) multiplexed in a third OFDMA signal receivedduring the TXOP, wherein the uplink LMRs may include per-STA timinginformation for the uplink sounding frames and the downlink soundingframes. The processing circuitry may be further configured to determinelocation measurements for the STAs based at least partly on the per-STAtiming information included in the uplink LMRs.

In Example 2, the subject matter of Example 1, wherein the processingcircuitry may be further configured to encode, for transmission duringthe TXOP, downlink LMRs multiplexed in a fourth OFDMA signal, whereinthe downlink LMRs include the location measurements.

In Example 3, the subject matter of one or any combination of Examples1-2, wherein the location measurements for the STAs are based ondistances between the AP and the STAs or angles of arrival between theAP and the STAs.

In Example 4, the subject matter of one or any combination of Examples1-3, wherein the per-STA timing information of a particular STA of theplurality is based at least partly on: a transmission time of the uplinksounding frame from the particular STA, and a reception time of thedownlink sounding frame for the particular STA at the particular STA.

In Example 5, the subject matter of one or any combination of Examples1-4, wherein the processing circuitry further configured to determinethe location measurement for the particular STA based at least partlyon: a difference between the reception time of the downlink soundingframe for the particular STA at the particular STA and the transmissiontime of the uplink sounding frame from the particular STA, and adifference between a transmission time, at the AP, of the downlinksounding frame for the particular STA and a reception time, at the AP,of the uplink sounding frame from the particular STA.

In Example 6, the subject matter of one or any combination of Examples1-5, wherein the processing circuitry may be further configured todetermine a transmit power to be used by a particular STA of theplurality based at least partly on a previously received uplink framefrom the particular STA.

In Example 7, the subject matter of one or any combination of Examples1-6, wherein the TF is a first TF. The processing circuitry may befurther configured to encode, for transmission, a second TF to schedulethe uplink LMRs.

In Example 8, the subject matter of one or any combination of Examples1-7, wherein the first TF may be a Trigger Frame for Location (TFL). Thefirst TF may include a TF type parameter that indicates a TF type from agroup of candidate TF types that includes at least the TFL.

In Example 9, the subject matter of one or any combination of Examples1-8, wherein the channel may comprise multiple resource units (RUs). Thefirst TF may include first RU allocation information for one or more ofthe STAs for the uplink sounding waveforms of the first OFDMA signal.The second TF may include second RU allocation information for one ormore of the STAs for the uplink LMRs of the third OFDMA signal.

In Example 10, the subject matter of one or any combination of Examples1-9, wherein the uplink sounding frames may comprise training symbolsfor uplink channel state information (CSI) estimation. The downlinksounding frames may comprise training symbols for downlink CSIestimation.

In Example 11, the subject matter of one or any combination of Examples1-10, wherein the location measurements may be determined as part of amulti-user (MU) location measurement. The TF is a second TF. Theprocessing circuitry may be further configured to encode, fortransmission, a first TF to initiate the MU location measurement. Theprocessing circuitry may be further configured to decode servicerequests for the MU location measurement from one or more STAs of theplurality of STAs. The processing circuitry may be further configured toencode, for transmission, an MU acknowledgement (ACK) frame thatindicates reception of the service requests.

In Example 12, the subject matter of one or any combination of Examples1-11, wherein the first TF may be a Trigger Frame for Random AccessService Request (TFR SR). The channel may comprise multiple resourceunits (RUs). The TFR SR may be configurable to allocate at least a firstRU to a particular associated STA for a service request from theparticular associated STA. The TFR SR may be further configurable toallocate at least a second RU for contention based transmission ofservice requests by unassociated STAs.

In Example 13, the subject matter of one or any combination of Examples1-12, wherein the AP may be arranged to operate in accordance with awireless local area network (WLAN) protocol.

In Example 14, the subject matter of one or any combination of Examples1-13, wherein the processing circuitry may be further configured tostore the location measurements for the STAs in the memory. Theprocessing circuitry may be further configured to determine a modulationand coding scheme (MCS) for a particular STA based at least partly onthe location measurement of the particular STA.

In Example 15, the subject matter of one or any combination of Examples1-14, wherein the processing circuitry may include a baseband processorto determine the location measurements for the STAs.

In Example 16, the subject matter of one or any combination of Examples1-15, wherein the apparatus may further include a transceiver to receivethe first and second OFDMA signals and to transmit the MU ACK frame.

In Example 17, a non-transitory computer-readable storage medium maystore instructions for execution by one or more processors to performoperations for communication by an access point (AP). The operations mayconfigure the one or more processors to contend for a transmissionopportunity (TXOP) to obtain access to a channel. The operations mayfurther configure the one or more processors to encode, fortransmission, a trigger frame (TF) to initiate a multi-user (MU)location measurement during the TXOP. The operations may furtherconfigure the one or more processors to decode service requests for theMU location measurement from a plurality of stations (STAs), the servicerequests multiplexed in a first orthogonal frequency division multipleaccess (OFDMA) signal. The operations may further configure the one ormore processors to encode, for transmission, an MU acknowledgement (ACK)frame that indicates reception of the service requests. The operationsmay further configure the one or more processors to decode, from theSTAs, uplink sounding frames that include per-STA timing information forthe service requests and the MU ACK frame, the uplink sounding framesmultiplexed in a second OFDMA signal. The operations may furtherconfigure the one or more processors to determine location measurementsfor the STAs based at least partly on the per-STA timing informationincluded in the uplink sounding frames.

In Example 18, the subject matter of Example 17, wherein the locationmeasurements for the STAs may be based on distances between the AP andthe STAs or angles of arrival between the AP and the STAs. The per-STAtiming information of a particular STA of the plurality may be based atleast partly on a transmission time of the service request from theparticular STA, and a reception time of the MU ACK frame at theparticular STA.

In Example 19, the subject matter of one or any combination of Examples17-18, wherein the operations may further configure the one or moreprocessors to encode, for transmission, downlink sounding frames thatinclude the determined location measurements for the STAs, the downlinksounding frames multiplexed in a third OFDMA signal.

In Example 20, the subject matter of one or any combination of Examples17-19, wherein the uplink sounding frames may further include uplinksounding waveforms. The processing circuitry may be further configuredto determine per-STA channel state information (CSI) based on the uplinksounding waveforms. The downlink sounding frames may include the per-STACSI and further include downlink sounding waveforms.

In Example 21, the subject matter of one or any combination of Examples17-20, wherein the uplink sounding frames may further include uplinklocation measurement reports (LMRs) that include the per-STA timinginformation.

In Example 22, the subject matter of one or any combination of Examples17-21, wherein the TF and the MU ACK frame may be encoded fortransmission during the TXOP. The first and second OFDMA signals may bereceived during the TXOP.

In Example 23, a method of sounding at a station (STA) may comprisedecoding a trigger frame (TF) that indicates that a plurality ofstations (STAs) are to transmit uplink sounding frames during atransmission opportunity (TXOP) obtained by an access point (AP). Themethod may further comprise encoding, for transmission during the TXOP,an uplink sounding frame multiplexed in a first orthogonal frequencydivision multiple access (OFDMA) signal, the uplink sounding framecomprising training symbols for uplink channel state information (CSI)estimation. The method may further comprise decoding a downlink soundingframe comprising training symbols for downlink CSI estimation, thedownlink sounding frame multiplexed in a second OFDMA signal receivedduring the TXOP. The method may further comprise encoding, fortransmission during the TXOP, an uplink location measurement report(LMR) that includes timing information for the transmission of theuplink sounding frame and the downlink sounding frames. The method mayfurther comprise decoding a downlink LMR received during the TXOP,wherein the downlink LMR includes a location measurement for the STAbased at least partly on the timing information included in the uplinkLMR.

In Example 24, the subject matter of Example 23, wherein the uplink LMRmay be multiplexed in a third OFDMA signal. The downlink LMR may bemultiplexed in a fourth OFDMA signal.

In Example 25, an apparatus of a station (STA) may comprise memory. Theapparatus may further comprise processing circuitry. The processingcircuitry may be configured to decode a trigger frame (TF) receivedduring a transmission opportunity (TXOP) obtained by an access point(AP). The processing circuitry may be further configured to encode, fortransmission and in response to the TF, a service request for a locationmeasurement of the STA as part of a multi-user (MU) location measurementby the AP. The service request may be multiplexed in a first orthogonalfrequency division multiple access (OFDMA) signal. The processingcircuitry may be further configured to decode an MU acknowledgement(ACK) frame that indicates reception of the service request. Theprocessing circuitry may be further configured to encode, fortransmission, an uplink sounding frame that includes timing informationbased at least partly on a transmission time of the service request anda reception time of the MU ACK frame. The uplink sounding frame may bemultiplexed in a second OFDMA signal. The processing circuitry may befurther configured to decode a downlink sounding frame that includes thelocation measurement for the STA. The location measurement may be basedon the timing information.

In Example 26, the subject matter of Example 25, wherein the downlinksounding frame may be multiplexed in a third OFDMA signal.

In Example 27, the subject matter of one or any combination of Examples25-26, wherein the TF is a first TF. The processing circuitry may befurther configured to decode a second TF. The service request may beencoded for transmission in a first resource unit (RU) of channelresources indicated by the first TF. The uplink sounding frame may beencoded for transmission in a second RU of the channel resourcesindicated by the second TF.

In Example 28, an apparatus of an access point (AP) may comprise memory.The apparatus may further comprise processing circuitry. The processingcircuitry may be configured to contend for a transmission opportunity(TXOP) to obtain access to a channel. The processing circuitry may befurther configured to encode, for transmission during the TXOP, atrigger frame (TF) to indicate that a plurality of stations (STAs) areto transmit uplink sounding frames. The processing circuitry may befurther configured to decode the uplink sounding frames multiplexed in afirst orthogonal frequency division multiple access (OFDMA) signalreceived during the TXOP. The processing circuitry may be furtherconfigured to encode, for transmission during the TXOP, downlinksounding frames multiplexed in a second OFDMA signal.

In Example 29, the subject matter of Example 28, wherein the processingcircuitry may be further configured to decode uplink locationmeasurement reports (LMRs) multiplexed in a third OFDMA signal receivedduring the TXOP. The uplink LMRs may include per-STA timing informationfor the uplink sounding frames and the downlink sounding frames. Theprocessing circuitry may be further configured to determine locationmeasurements for the STAs based at least partly on the per-STA timinginformation included in the uplink LMRs.

In Example 30, an apparatus of an access point (AP) may comprise meansfor contending for a transmission opportunity (TXOP) to obtain access toa channel. The apparatus may further comprise means for encoding, fortransmission, a trigger frame (TF) to initiate a multi-user (MU)location measurement during the TXOP. The apparatus may further comprisemeans for decoding service requests for the MU location measurement froma plurality of stations (STAs), the service requests multiplexed in afirst orthogonal frequency division multiple access (OFDMA) signal. Theapparatus may further comprise means for encoding, for transmission, anMU acknowledgement (ACK) frame that indicates reception of the servicerequests. The apparatus may further comprise means for decoding, fromthe STAs, uplink sounding frames that include per-STA timing informationfor the service requests and the MU ACK frame, the uplink soundingframes multiplexed in a second OFDMA signal. The apparatus may furthercomprise means for determining location measurements for the STAs basedat least partly on the per-STA timing information included in the uplinksounding frames.

In Example 31, the subject matter of Example 30, wherein the locationmeasurements for the STAs may be based on distances between the AP andthe STAs or angles of arrival between the AP and the STAs. The per-STAtiming information of a particular STA of the plurality may be based atleast partly on a transmission time of the service request from theparticular STA, and a reception time of the MU ACK frame at theparticular STA.

In Example 32, the subject matter of one or any combination of Examples30-31, wherein the apparatus may further comprise means for encoding,for transmission, downlink sounding frames that include the determinedlocation measurements for the STAs, the downlink sounding framesmultiplexed in a third OFDMA signal.

In Example 33, the subject matter of one or any combination of Examples30-32, wherein the uplink sounding frames may further include uplinksounding waveforms. The apparatus may further comprise means fordetermining per-STA channel state information (CSI) based on the uplinksounding waveforms. The downlink sounding frames may include the per-STACSI and further include downlink sounding waveforms.

In Example 34, the subject matter of one or any combination of Examples30-33, wherein the uplink sounding frames may further include uplinklocation measurement reports (LMRs) that include the per-STA timinginformation.

In Example 35, the subject matter of one or any combination of Examples30-34, wherein the TF and the MU ACK frame may be encoded fortransmission during the TXOP. The first and second OFDMA signals may bereceived during the TXOP.

The Abstract is provided to comply with 37 C.F.R. Section 1.72(b)requiring an abstract that will allow the reader to ascertain the natureand gist of the technical disclosure. It is submitted with theunderstanding that it will not be used to limit or interpret the scopeor meaning of the claims. The following claims are hereby incorporatedinto the detailed description, with each claim standing on its own as aseparate embodiment.

What is claimed is:
 1. An apparatus of an access point (AP), the apparatus comprising: memory; and processing circuitry, configured to: contend for a transmission opportunity (TXOP) to obtain access to a channel; encode, for transmission during the TXOP, a trigger frame (TF) to indicate that a plurality of stations (STAs) are to transmit uplink sounding frames; decode the uplink sounding frames multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal received during the TXOP; encode, for transmission during the TXOP, downlink sounding frames multiplexed in a second OFDMA signal; decode uplink location measurement reports (LMRs) multiplexed in a third OFDMA signal received during the TXOP, wherein the uplink LMRs include per-STA timing information for the uplink sounding frames and the downlink sounding frames; and determine location measurements for the STAs based at least partly on the per-STA timing information included in the uplink LMRs.
 2. The apparatus according to claim 1, the processing circuitry further configured to: encode, for transmission during the TXOP, downlink LMRs multiplexed in a fourth OFDMA signal, wherein the downlink LMRs include the location measurements.
 3. The apparatus according to claim 1, wherein the location measurements for the STAs are based on distances between the AP and the STAs or angles of arrival between the AP and the STAs.
 4. The apparatus according to claim 1, wherein: the per-STA timing information of a particular STA of the plurality is based at least partly on: a transmission time of the uplink sounding frame from the particular STA, and a reception time of the downlink sounding frame for the particular STA at the particular STA.
 5. The apparatus according to claim 4, the processing circuitry further configured to: determine the location measurement for the particular STA based at least partly on: a difference between the reception time of the downlink sounding frame for the particular STA at the particular STA and the transmission time of the uplink sounding frame from the particular STA, and a difference between a transmission time, at the AP, of the downlink sounding frame for the particular STA and a reception time, at the AP, of the uplink sounding frame from the particular STA.
 6. The apparatus according to claim 1, the processing circuitry further configured to: determine a transmit power to be used by a particular STA of the plurality based at least partly on a previously received uplink frame from the particular STA.
 7. The apparatus according to claim 1, wherein: the TF is a first TF, the processing circuitry is further configured to encode, for transmission, a second TF to schedule the uplink LMRs.
 8. The apparatus according to claim 7, wherein: the first TF is a Trigger Frame for Location (TFL), the first TF includes a TF type parameter that indicates a TF type from a group of candidate TF types that includes at least the TFL.
 9. The apparatus according to claim 7, wherein: the channel comprises multiple resource units (RUs), the first TF includes first RU allocation information for one or more of the STAs for the uplink sounding waveforms of the first OFDMA signal, and the second TF includes second RU allocation information for one or more of the STAs for the uplink LMRs of the third OFDMA signal.
 10. The apparatus according to claim 1, wherein: the uplink sounding frames comprise training symbols for uplink channel state information (CSI) estimation, and the downlink sounding frames comprise training symbols for downlink CSI estimation.
 11. The apparatus according to claim 1, wherein: the location measurements are determined as part of a multi-user (MU) location measurement, the TF is a second TF, the processing circuitry is further configured to: encode, for transmission, a first TF to initiate the MU location measurement; decode service requests for the MU location measurement from one or more STAs of the plurality of STAs; and encode, for transmission, an MU acknowledgement (ACK) frame that indicates reception of the service requests.
 12. The apparatus according to claim 11, wherein: the first TF is a Trigger Frame for Random Access Service Request (TFR SR), the channel comprises multiple resource units (RUs), the TFR SR is configurable to allocate at least a first RU to a particular associated STA for a service request from the particular associated STA, and the TFR SR is further configurable to allocate at least a second RU for contention based transmission of service requests by unassociated STAs.
 13. The apparatus according to claim 1, wherein the AP is arranged to operate in accordance with a wireless local area network (WLAN) protocol.
 14. The apparatus according to claim 1, the processing circuitry further configured to: store the location measurements for the STAs in the memory; and determine a modulation and coding scheme (MCS) for a particular STA based at least partly on the location measurement of the particular STA.
 15. The apparatus according to claim 1, wherein the processing circuitry includes a baseband processor to determine the location measurements for the STAs.
 16. The apparatus according to claim 1, wherein the apparatus further includes a transceiver to receive the first and second OFDMA signals and to transmit the MU ACK frame.
 17. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations for communication by an access point (AP), the operations to configure the one or more processors to: contend for a transmission opportunity (TXOP) to obtain access to a channel; encode, for transmission, a trigger frame (TF) to initiate a multi-user (MU) location measurement during the TXOP; decode service requests for the MU location measurement from a plurality of stations (STAs), the service requests multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal; encode, for transmission, an MU acknowledgement (ACK) frame that indicates reception of the service requests; decode, from the STAs, uplink sounding frames that include per-STA timing information for the service requests and the MU ACK frame, the uplink sounding frames multiplexed in a second OFDMA signal; and determine location measurements for the STAs based at least partly on the per-STA timing information included in the uplink sounding frames.
 18. The non-transitory computer-readable storage medium according to claim 17, wherein: the location measurements for the STAs are based on distances between the AP and the STAs or angles of arrival between the AP and the STAs, and the per-STA timing information of a particular STA of the plurality is based at least partly on: a transmission time of the service request from the particular STA, and a reception time of the MU ACK frame at the particular STA.
 19. The non-transitory computer-readable storage medium according to claim 17, the operations to further configure the one or more processors to: encode, for transmission, downlink sounding frames that include the determined location measurements for the STAs, the downlink sounding frames multiplexed in a third OFDMA signal.
 20. The non-transitory computer-readable storage medium according to claim 19, wherein: the uplink sounding frames further include uplink sounding waveforms, the processing circuitry is further configured to determine per-STA channel state information (CSI) based on the uplink sounding waveforms, the downlink sounding frames include the per-STA CSI and further include downlink sounding waveforms.
 21. The non-transitory computer-readable storage medium according to claim 17, wherein: the uplink sounding frames further include uplink location measurement reports (LMRs) that include the per-STA timing information.
 22. The non-transitory computer-readable storage medium according to claim 17, wherein: the TF and the MU ACK frame are encoded for transmission during the TXOP, and the first and second OFDMA signals are received during the TXOP.
 23. A method of sounding at a station (STA), the method comprising: decoding a trigger frame (TF) that indicates that a plurality of stations (STAs) are to transmit uplink sounding frames during a transmission opportunity (TXOP) obtained by an access point (AP); encoding, for transmission during the TXOP, an uplink sounding frame multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal, the uplink sounding frame comprising training symbols for uplink channel state information (CSI) estimation; decoding a downlink sounding frame comprising training symbols for downlink CSI estimation, the downlink sounding frame multiplexed in a second OFDMA signal received during the TXOP; encoding, for transmission during the TXOP, an uplink location measurement report (LMR) that includes timing information for the transmission of the uplink sounding frame and the downlink sounding frames; and decoding a downlink LMR received during the TXOP, wherein the downlink LMR includes a location measurement for the STA based at least partly on the timing information included in the uplink LMR.
 24. The method according to claim 23, wherein: the uplink LMR is multiplexed in a third OFDMA signal, and the downlink LMR is multiplexed in a fourth OFDMA signal.
 25. An apparatus of a station (STA), the apparatus comprising: memory; and processing circuitry, configured to: decode a trigger frame (TF) received during a transmission opportunity (TXOP) obtained by an access point (AP); encode, for transmission and in response to the TF, a service request for a location measurement of the STA as part of a multi-user (MU) location measurement by the AP, wherein the service request is multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal; decode an MU acknowledgement (ACK) frame that indicates reception of the service request; encode, for transmission, an uplink sounding frame that includes timing information based at least partly on a transmission time of the service request and a reception time of the MU ACK frame, wherein the uplink sounding frame is multiplexed in a second OFDMA signal; and decode a downlink sounding frame that includes the location measurement for the STA, the location measurement based on the timing information.
 26. The apparatus according to claim 25, wherein the downlink sounding frame is multiplexed in a third OFDMA signal.
 27. The apparatus according to claim 25, wherein: the TF is a first TF, the processing circuitry may be further configured to decode a second TF, the service request is encoded for transmission in a first resource unit (RU) of channel resources indicated by the first TF, the uplink sounding frame is encoded for transmission in a second RU of the channel resources indicated by the second TF.
 28. An apparatus of an access point (AP), the apparatus comprising: memory; and processing circuitry, configured to: contend for a transmission opportunity (TXOP) to obtain access to a channel; encode, for transmission during the TXOP, a trigger frame (TF) to indicate that a plurality of stations (STAs) are to transmit uplink sounding frames; decode the uplink sounding frames multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal received during the TXOP; and encode, for transmission during the TXOP, downlink sounding frames multiplexed in a second OFDMA signal.
 29. The apparatus according to claim 28, the processing circuitry further configured to: decode uplink location measurement reports (LMRs) multiplexed in a third OFDMA signal received during the TXOP, wherein the uplink LMRs include per-STA timing information for the uplink sounding frames and the downlink sounding frames; and determine location measurements for the STAs based at least partly on the per-STA timing information included in the uplink LMRs. 